Bile acids: Analysis in biological fluids and tissues

Journal of Lipid Research

Volumn 51, Issue 1, 2010, Pages 23-41

  Griffiths, William J ^a   Sjövall, Jan ^b  

^a SWANSEA UNIVERSITY   (United Kingdom)

^b KAROLINSKA INSTITUTE   (Sweden)

Author keywords

Electrospray ionization; Gas liquid chromatography mass spectrometry; Liquid chromatography mass spectrometry; Sample preparation

Indexed keywords

BILE ACID;

BILE ACID METABOLISM; BILE ACID SYNTHESIS; CAPILLARY CHROMATOGRAPHY; DERIVATIZATION; ELECTROSPRAY MASS SPECTROMETRY; ENZYME ASSAY; FAST ATOM BOMBARDMENT MASS SPECTROMETRY; HEAT TREATMENT; HIGH PERFORMANCE LIQUID CHROMATOGRAPHY; HUMAN; IMMUNOASSAY; LIQUID CHROMATOGRAPHY; MASS FRAGMENTOGRAPHY; MASS SPECTROMETRY; PRIORITY JOURNAL; PROTEIN CLEAVAGE; REVIEW; SENSITIVITY ANALYSIS; SOLVENT EXTRACTION; ULTRASOUND;

ANIMALS; BILE ACIDS AND SALTS; BODY FLUIDS; CHOLESTANOLS; CHROMATOGRAPHY, HIGH PRESSURE LIQUID; GAS CHROMATOGRAPHY-MASS SPECTROMETRY; HUMANS; MASS SPECTROMETRY; SPECTROMETRY, MASS, ELECTROSPRAY IONIZATION;

EID: 73149099639     PISSN: 00222275     EISSN: 15397262     Source Type: Journal    
DOI: 10.1194/jlr.R001941-JLR200     Document Type: Review

References (182)

1. Motola, D. L., C. L. Cummins, V. Rottiers, K. K. Sharma, T. Li, Y. Li, K. Suino-Powell, H. E. Xu, R. J. Auchus, A. Antebi, et al. 2006. Identification of ligands for DAF-12 that govern dauer formation and reproduction in C. elegans. Cell. 124: 1209-1223.
2. Maneerat, S., T. Nitoda, H. Kanzaki, and F. Kawai. 2005. Bile acids are new products of a marine bacterium, Myroides sp. strain SM1. Appl. Microbiol. Biotechnol. 67: 679-683.
3. Sobotka, H. (1937) Physiological chemistry of the bile. Ballière, Tyndall & Cox, London.
4. Sobotka, H. (1938) Chemistry of the sterids. Ballière, Tyndall & Cox, London.
5. Bergström, S., H. Danielsson, and B. Samuelsson. (1960) Formation and metabolism of bile acids. In Lipide Metabolism. K. Block, editor. John Wiley & Sons, New York. 291-366.
6. Eneroth, P., and J. Sjövall. (1971) Extraction, purification and chromatographic analysis of bile acids in biological materials. In The Bile Acids, Volume 1. D. Kritchevsky and P. P. Nair, editors. Plenum Press, New York. 209-248.
7. Horning, E. C., C. J. Brooks, and W. J. Vanden Heuvel. 1968. Gas phase analytical methods for the study of steroids. Adv. Lipid Res. 6: 273-392.
8. Ryhage, R. 1964. Use of a mass spectrometer as a detector and analyzer for effluents emerging from high temperature gas liquid chromatography columns. Anal. Chem. 36: 759-764.
9. Sjövall, J., P. Eneroth, and R. Ryhage. (1971) Mass spectra of bile acids. In The Bile Acids; Chemistry, Physiology and Metabolism. P. Nair and D. Kritchevsky, editors. Plenum Press, New York.
10. Murphy, G. M., M. Maghsoudloo, and M. Y. Qureshi. (1995) Assay of bile acids in biological samples. In Steroid Analysis. H. L. J. Makin, D. B. Gower, and D. B. Kirk, editors. Blackie Academic & Professional, Glasgow. 527-561.
11. Simmonds, W. J., M. G. Korman, V. L. Go, and A. F. Hofmann. 1973. Radioimmunoassay of conjugated cholyl bile acids in serum. Gastroenterology. 65: 705-711.
12. Shaw, R., and W. H. Elliott. 1976. Bile acids. XLVIII. Separation of conjugated bile acids by high-pressure liquid chromatography. Anal. Biochem. 74: 273-281.
13. Roda, A., A. M. Gioacchini, C. Cerre, and M. Baraldini. 1995. High-performance liquid chromatographic-electrospray mass spectrometric analysis of bile acids in biological fluids. J. Chromatogr. B Biomed. Appl. 665: 281-294.
14. Russell, D. W., and K. D. Setchell. 1992. Bile acid biosynthesis. Biochemistry. 31: 4737-4749.
15. Une, M., and T. Hoshita. 1994. Natural occurrence and chemical synthesis of bile alcohols, higher bile acids, and short side chain bile acids. Hiroshima J. Med. Sci. 43: 37-67.
16. Russell, D. W. 2003. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72: 137-174.
17. Mitamura, K., S. Watanabe, Y. Mitsumoto, T. Sakai, M. Sogabe, T. Wakamiya, and S. Ikegawa. 2009. Formation and biliary excretion of glutathione conjugates of bile acids in the rat as shown by liquid chromatography/electrospray ionization-linear ion trap mass spectrometry. Anal. Biochem. 384: 224-230.
18. Sorensen, P. W., J. M. Fine, V. Dvornikovs, C. S. Jeffrey, F. Shao, J. Wang, L. A. Vrieze, K. R. Anderson, and T. R. Hoye. 2005. Mixture of new sulfated steroids functions as a migratory pheromone in the sea lamprey. Nat. Chem. Biol. 1: 324-328.
19. Fine, J. M., and P. W. Sorensen. 2005. Biologically relevant concentrations of petromyzonol sulfate, a component of the sea lamprey migratory pheromone, measured in stream water. J. Chem. Ecol. 31: 2205-2210.
20. Parmentier, G., J. Mertens, and H. Eyssen. (1975) Cholic acid-7-sulfate, a major bile acid in the large intestine of mouse. In Advances in Bile Acid Research. S. Matern, J. Hackenschmidt, and P. Back, editors. Schattauer Verlag, Stuttgart. 39-144.
21. Eyssen, H. J., G. G. Parmentier, and J. A. Mertens. 1976. Sulfate bile acids in germ-free and conventional mice. Eur. J. Biochem. 66: 507-514.
22. Norman, A., and R. H. Palmer. 1964. Metabolites of lithocholic acid-24-C-14 in human bile and feces. J. Lab. Clin. Med. 63: 986-1001.
23. Kelsey, M. I., J. E. Molina, S. K. Huang, and K. K. Hwang. 1980. The identification of microbial metabolites of sulfolithocholic acid. J. Lipid Res. 21: 751-759.
24. Korpela, J. T., T. Fotsis, and H. Adlercreutz. 1986. Multicomponent analysis of bile acids in faeces by anion exchange and capillary column gas-liquid chromatography: application in oxytetracycline treated subjects. J. Steroid Biochem. 25: 277-284.
25. Benson, G. M., N. J. Haskins, C. Eckers, P. J. Moore, D. G. Reid, R. C. Mitchell, S. Waghmare, and K. E. Suckling. 1993. Polydeoxycholate in human and hamster feces: a major product of cholate metabolism. J. Lipid Res. 34: 2121-2134.
26. Alvelius, G., O. Hjalmarson, W. J. Griffiths, I. Björkhem, and J. Sjövall. 2001. Identification of unusual 7-oxygenated bile acid sulfates in a patient with Niemann-Pick disease, type C. J. Lipid Res. 42: 1571-1577.
27. Iida, T., G. Kakiyama, Y. Hibiya, S. Miyata, T. Inoue, K. Ohno, T. Goto, N. Mano, J. Goto, T. Nambara, et al. 2006. Chemical synthesis of the 3-sulfooxy-7-N-acetylglucosaminyl-24-amidated conjugates of 3beta,7beta-dihydroxy-5-cholen-24-oic acid, and related compounds: unusual, major metabolites of bile acid in a patient with Niemann-Pick disease type C1. Steroids. 71: 18-29.
28. Setchell, K. D., M. Schwarz, N. C. O'Connell, E. G. Lund, D. L. Davis, R. Lathe, H. R. Thompson, T. R. Weslie, R. J. Sokol, and D. W. Russell. 1998. Identification of a new inborn error in bile acid synthesis: mutation of the oxysterol 7alpha-hydroxylase gene causes severe neonatal liver disease. J. Clin. Invest. 102: 1690-1703.
29. Setchell, K. D., J. E. Heubi, K. E. Bove, N. C. O'Connell, T. Brewsaugh, S. J. Steinberg, A. Moser, and R. H. Squires, Jr. 2003. Liver disease caused by failure to racemize trihydroxy-cholestanoic acid: gene mutation and effect of bile acid therapy. Gastroenterology. 124: 217-232.
30. Setchell, K. D., and J. E. Heubi. 2006. Defects in bile acid biosynthesis-diagnosis and treatment. J. Pediatr. Gastroenterol. Nutr. 43 (Suppl 1): S17-S22.
31. Lemonde, H. A., A. W. Johnson, and P. T. Clayton. 1999. The identification of unusual bile acid metabolites by tandem mass spectrometry: use of low-energy collision-induced dissociation to produce informative spectra. Rapid Commun. Mass Spectrom. 13: 1159-1164.
32. Lemonde, H. A., E. J. Custard, J. Bouquet, M. Duran, H. Overmars, P. J. Scambler, and P. T. Clayton. 2003. Mutations in SRD5B1 (AKR1D1), the gene encoding delta(4)-3-oxosteroid 5beta-reductase, in hepatitis and liver failure in infancy. Gut. 52: 1494-1499.
33. Clayton, P. T., A. Verrips, E. Sistermans, A. Mann, G. Mieli-Vergani, and R. Wevers. 2002. Mutations in the sterol 27-hydroxylase gene (CYP27A) cause hepatitis of infancy as well as cerebrotendinous xanthomatosis. J. Inherit. Metab. Dis. 25: 501-513.
34. Clayton, P. T. 2003. Diagnosis of inherited disorders of liver metabolism. J. Inherit. Metab. Dis. 26: 135-146.
35. Egestad, B., P. Pettersson, S. Skrede, and J. Sjövall. 1985. Fast atom bombardment mass spectrometry in the diagnosis of cerebrotendinous xanthomatosis. Scand. J. Clin. Lab. Invest. 45: 443-446.
36. Clayton, P. T., J. V. Leonard, A. M. Lawson, K. D. Setchell, S. Andersson, B. Egestad, and J. Sjövall. 1987. Familial giant cell hepatitis associated with synthesis of 3 beta, 7 alpha-dihydroxy- and 3 beta,7 alpha, 12 alpha-trihydroxy-5-cholenoic acids. J. Clin. Invest. 79: 1031-1038.
37. Fischler, B., K. Bodin, H. Stjernman, M. Olin, M. Hansson, J. Sjövall, and I. Björkhem. 2007. Cholestatic liver disease in adults may be due to an inherited defect in bile acid biosynthesis. J. Intern. Med. 262: 254-262.
38. Yang, Y., W. J. Griffiths, H. Nazer, and J. Sjövall. 1997. Analysis of bile acids and bile alcohols in urine by capillary column liquid chromatography-mass spectrometry using fast atom bombardment or electrospray ionization and collision-induced dissociation. Biomed. Chromatogr. 11: 240-255.
39. Meng, L. J., W. J. Griffiths, H. Nazer, Y. Yang, and J. Sjövall. 1997. High levels of (24S)-24-hydroxycholesterol 3-sulfate, 24-glucuronide in the serum and urine of children with severe cholestatic liver disease. J. Lipid Res. 38: 926-934.
40. Griffiths, W. J. 2003. Tandem mass spectrometry in the study of fatty acids, bile acids, and steroids. Mass Spectrom. Rev. 22: 81-152.
41. Wang, Y., and W. J. Griffiths. (2008) Mass spectrometry for metabolite identification. In Metabolomics, Metabonomics and Metabolite Profiling. W. J. Griffiths, editor. The Royal Society of Chemistry, Cambridge. 1-31.
42. Hager, J. W., and J. C. Yves Le Blanc. 2003. Product ion scanning using a Q-q-Q linear ion trap (Q TRAP) mass spectrometer. Rapid Commun. Mass Spectrom. 17: 1056-1064.
43. Ikegawa, S., H. Okuyama, J. Oohashi, N. Murao, and J. Goto. 1999. Separation and detection of bile acid 24-glucuronides in human urine by liquid chromatography combined with electrospray ionization mass spectrometry. Anal. Sci. 15: 625-631.
44. Libert, R., D. Hermans, J. P. Draye, F. Van Hoof, E. Sokal, and E. de Hoffmann. 1991. Bile acids and conjugates identified in metabolic disorders by fast atom bombardment and tandem mass spectrometry. Clin. Chem. 37: 2102-2110.
45. Mushtaq, I., S. Logan, M. Morris, A. W. Johnson, A. M. Wade, D. Kelly, and P. T. Clayton. 1999. Screening of newborn infants for cholestatic hepatobiliary disease with tandem mass spectrometry. BMJ. 319: 471-477.
46. Yousef, I. M., S. Perwaiz, T. Lamireau, and B. Tuchweber. 2003. Urinary bile acid profile in children with inborn errors of bile acid metabolism and chronic cholestasis; screening technique using electrospray tandem mass-spectrometry (ES/MS/MS). Med. Sci. Monit. 9: MT21-MT31.
47. Stroobant, V., E. de Hoffmann, R. Libert, and F. Van Hoof. 1995. Fast-atom bombardment mass spectrometry and low energy collision-induced tandem mass spectrometry of tauroconjugated bile acid anions. J. Am. Soc. Mass Spectrom. 6: 588-596.
48. Tomer, K. B., and M. L. Gross. 1988. Fast atom bombardment and tandem mass spectrometry for structure determination: remote site fragmentation of steroid conjugates and bile salts. Biomed. Environ. Mass Spectrom. 15: 89-98.
49. Zhang, J., W. J. Griffiths, T. Bergman, and J. Sjövall. 1993. Derivatization of bile acids with taurine for analysis by fast atom bombardment mass spectrometry with collision-induced fragmentation. J. Lipid Res. 34: 1895-1900.
50. Pittenauer, E., and G. Allmaier. 2009. High-energy collision induced dissociation of biomolecules: MALDI-TOF/RTOF mass spectrometry in comparison to tandem sector mass spectrometry. Comb. Chem. High Throughput Screen. 12: 137-155.
51. Mims, D., and D. Hercules. 2003. Quantification of bile acids directly from urine by MALDI-TOF-MS. Anal. Bioanal. Chem. 375: 609-616.
52. Mims, D., and D. Hercules. 2004. Quantification of bile acids directly from plasma by MALDI-TOF-MS. Anal. Bioanal. Chem. 378: 1322-1326.
53. Sjövall, J., and K. D. Setchell. (1988) Techniques for extraction and group separation of bile acids. In The Bile Acids. Vol. 4. K. D. Setchell, D. Kritchevsky, and P. P. Nair, editors. Plenum Press, New York. 1-42.
54. Perwaiz, S., D. Mignault, B. Tuchweber, and I. M. Yousef. 2002. Rapid and improved method for the determination of bile acids in human feces using MS. Lipids. 37: 1093-1100.
55. Alnouti, Y., I. L. Csanaky, and C. D. Klaassen. 2008. Quantitative-profiling of bile acids and their conjugates in mouse liver, bile, plasma, and urine using LC-MS/MS. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 873: 209-217.
56. Axelson, M., and J. Sjövall. (1985) Studies on the selective analysis of ketonic bile acids and steroids in faeces. In Enterohepatic Circulation of Bile Acids and Sterol Metabolism. G. Paumgartner, A. Stiehl, and W. Gerok, editors. MTP Press Ltd, Lancaster, UK. 249-258
57. Setchell, K. D., J. M. Street, and J. Sjövall. (1988) Fecal bile acids. In The Bile Acids: Methods and Applications. K. D. Setchell, D. Kritchevsky, and P. P. Nair, editors. Plenum Press, New York. 441-570.
58. Setchell, K. D., A. M. Lawson, N. Tanida, and J. Sjövall. 1983. General methods for the analysis of metabolic profiles of bile acids and related compounds in feces. J. Lipid Res. 24: 1085-1100.
59. Eneroth, P., K. Hellström, and J. Sjövall. 1968. A method for quantitative determination of bile acids in human feces. Bile acids and steroids 195. Acta Chem. Scand. 22: 1729-1744.
60. Gustafsson, B. E., and A. Norman. 1969. Influence of the diet on the turnover of bile acids in germ-free and conventional rats. Br. J. Nutr. 23: 429-442.
61. Hedenborg, G., A. Norlander, and A. Norman. 1986. Bile acid conjugates present in tissues during extrahepatic cholestasis. Scand. J. Clin. Lab. Invest. 46: 539-544.
62. Batta, A. K., G. Salen, K. R. Rapole, M. Batta, P. Batta, D. Alberts, and D. Earnest. 1999. Highly simplified method for gas-liquid chromatographic quantitation of bile acids and sterols in human stool. J. Lipid Res. 40: 1148-1154.
63. Setchell, K. D., J. A. Ives, G. C. Cashmore, and A. M. Lawson. 1987. On the homogeneity of stools with respect to bile acid composition and normal day-to-day variations: a detailed qualitative and quantitative study using capillary column gas chromatography-mass spectrometry. Clin. Chim. Acta. 162: 257-275.
64. Haines, A., M. J. Hill, M. H. Thompson, R. W. Owen, R. E. Williams, T. W. Meade, H. Wilkes, and M. Griffin. 2000. A prospective study of faecal bile acids and colorectal cancer. Eur. J. Cancer Prev. 9: 317-323.
65. Mano, N., T. Goto, M. Uchida, K. Nishimura, M. Ando, N. Kobayashi, and J. Goto. 2004. Presence of protein-bound unconjugated bile acids in the cytoplasmic fraction of rat brain. J. Lipid Res. 45: 295-300.
66. Nuber, R., H. Maucher, and E. F. Stange. 1990. Size exclusion chromatography for extraction of serum bile acids. J. Lipid Res. 31: 1517-1522.
67. Axelson, M., and B-L. Sahlberg. 1981. On solid extraction of steroids and steroid conjugates in biological fluids. Anal. Lett. 14: 771-782.
68. Wahlén, E., N. Tamasawa, H. Ichimiya, B. Egestad, and J. Sjövall. 1994. Conditions for solid-phase extraction of urinary bile acids with octadecylsilane-bonded silica. J. Lipid Res. 35: 1902-1906.
69. Rodrigues, C. M., and K. D. Setchell. 1996. Performance characteristics of reversed-phase bonded silica cartridges for serum bile acid extraction. Biomed. Chromatogr. 10: 1-5.
70. Björkhem, I., U. Andersson, E. Ellis, G. Alvelius, L. Ellegård, U. Diczfalusy, J. Sjövall, and C. Einarsson. 2001. From brain to bile. Evidence that conjugation and omega-hydroxylation are important for elimination of 24S-hydroxycholesterol (cerebrosterol) in humans. J. Biol. Chem. 276: 37004-37010.
71. Persson, E., L. Löfgren, G. Hansson, B. Abrahamsson, H. Lennernäs, and R. Nilsson. 2007. Simultaneous assessment of lipid classes and bile acids in human intestinal fluid by solid-phase extraction and HPLC methods. J. Lipid Res. 48: 242-251.
72. Almé, B., A. Bremmelgaard, J. Sjövall, and P. Thomassen. 1977. Analysis of metabolic profiles of bile acids in urine using a lipophilic anion exchanger and computerized gas-liquid chromatography-mass spectrometry. J. Lipid Res. 18: 339-362.
73. Goto, J., M. Hasegawa, H. Kato, and T. Nambara. 1978. A new method for simultaneous determination of bile acids in human bile without hydrolysis. Clin. Chim. Acta. 87: 141-147.
74. Sjövall, J., and M. Axelson. 1984. Sample work-up by column techniques. J. Pharm. Biomed. Anal. 2: 265-280.
75. Axelson, M., B. Mörk, and J. Sjövall. 1988. Occurrence of 3 beta-hydroxy-5-cholestenoic acid, 3 beta,7 alpha-dihydroxy-5-cholestenoic acid, and 7 alpha-hydroxy-3-oxo-4-cholestenoic acid as normal constituents in human blood. J. Lipid Res. 29: 629-641.
76. Ichimiya, H., B. Egestad, H. Nazer, E. S. Baginski, P. T. Clayton, and J. Sjövall. 1991. Bile acids and bile alcohols in a child with hepatic 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase deficiency: effects of chenodeoxycholic acid treatment. J. Lipid Res. 32: 829-841.
77. Meng, L. J., and J. Sjövall. 1997. Method for combined analysis of profiles of conjugated progesterone metabolites and bile acids in serum and urine of pregnant women. J. Chromatogr. B Biomed. Sci. Appl. 688: 11-26.
78. Axelson, M., B. Mörk, and G. T. Everson. 1991. Bile acid synthesis in cultured human hepatoblastoma cells. J. Biol. Chem. 266: 17770-17777.
79. Axelson, M., E. Ellis, B. Mörk, K. Garmark, A. Abrahamsson, I. Björkhem, B. G. Ericzon, and C. Einarsson. 2000. Bile acid synthesis in cultured human hepatocytes: support for an alternative biosynthetic pathway to cholic acid. Hepatology. 31: 1305-1312.
80. Goto, J., H. Kato, Y. Saruta, and T. Nambara. 1981. Studies on steroids. CLXX. Separation and determination of bile acid 3-sulfates in human bile by high-performance liquid chromatography. J. Chromatogr. A. 226: 13-24.
81. Goto, J., H. Miura, M. Inada, T. Nambara, T. Nagakura, and H. Suzuki. 1988. Studies on steroids. CCXXXVIII. Determination of bile acids in liver tissue by gas chromatography-mass spectrometry with negative ion chemical ionization detection. J. Chromatogr. A. 452: 119-129.
82. Goto, J., N. Murao, C. Nakada, T. Motoyama, J. Oohashi, T. Yanagihara, T. Niwa, and S. Ikegawa. 1998. Separation and characterization of carboxyl-linked glucuronides of bile acids in incubation mixture of rat liver microsomes. Steroids. 63: 186-192.
83. Goto, T. 2007. Development of a highly sensitive methods for determination of activated carboxylic acids in biological specimens. Chromatography. 28: 9-17.
84. Ikegawa, S., N. Hirabayashi, T. Yoshimura, M. Tohma, M. Maeda, and A. Tsuji. 1992. Determination of conjugated bile acids in human urine by high-performance liquid chromatography with chemiluminescence detection. J. Chromatogr. A. 577: 229-238.
85. Ikegawa, S., T. Yoshimura, K. Ito, T. Kurosawa, and M. Tohma. 1995. Simultaneous flurometric determination of conjugated fetal bile acids in newborns by high-performance liquid chromatography. Anal. Sci. 11: 91-96.
86. Ikegawa, S., N. Murao, T. Motoyama, T. Yanagihara, T. Niwa, and J. Goto. 1996. Separation and detection of bile acid 3-glucuronides in human urine by liquid chromatography/electrospay ionization-mass spectrometry. Biomed. Chromatogr. 10: 313-317.
87. Marschall, H. U., G. Green, B. Egestad, and J. Sjövall. 1988. Isolation of bile acid glucosides and N-acetylglucosaminides from human urine by ion-exchange chromatography and reversed-phase high-performance liquid chromatography. J. Chromatogr. A. 452: 459-468.
88. Marschall, H. U., W. J. Griffiths, U. Gotze, J. Zhang, H. Wietholtz, N. Busch, J. Sjövall, and S. Matern. 1994. The major metabolites of ursodeoxycholic acid in human urine are conjugated with N-acetylglucosamine. Hepatology. 20: 845-853.
89. Matoba, N., M. Une, and T. Hoshita. 1986. Identification of unconjugated bile acids in human bile. J. Lipid Res. 27: 1154-1162.
90. Meng, L. J., H. Reyes, J. Palma, I. Hernandez, J. Ribalta, and J. Sjövall. 1997. Effects of ursodeoxycholic acid on conjugated bile acids and progesterone metabolites in serum and urine of patients with intrahepatic cholestasis of pregnancy. J. Hepatol. 27: 1029-1040.
91. Niwa, T., K. Fujita, J. Goto, and T. Nambara. 1993. Separation and characterization of ursodeoxycholate 7-N-acetylglucosaminides in human urine by high performance liquid chromatography with fluorescence detection. J. Liq. Chromatogr. 16: 2531-2544.
92. Une, M., K. Tsujimura, K. Kihira, and T. Hoshita. 1989. Identification of (22R)-3 alpha,7 alpha,12 alpha,22- and (23R)-3 alpha,7 alpha,12 alpha,23-tetrahydroxy-5 beta-cholestanoic acids in urine from a patient with Zellweger's syndrome. J. Lipid Res. 30: 541-547.
93. Wahlén, E., B. Egestad, B. Strandvik, and J. Sjövall. 1989. Ketonic bile acids in urine of infants during the neonatal period. J. Lipid Res. 30: 1847-1857.
94. Scalia, S. 1990. Group separation of free and conjugated bile acids by pre-packed anion-exchange cartridges. J. Pharm. Biomed. Anal. 8: 235-241.
95. Griffiths, W. J., M. Hornshaw, G. Woffendin, S. F. Baker, A. Lockhart, S. Heidelberger, M. Gustafsson, J. Sjövall, and Y. Wang. 2008. Discovering oxysterols in plasma: a window on the metabolome. J. Proteome Res. 7: 3602-3612.
96. Scalia, S. 1995. Bile acid separation. J. Chromatogr. B Biomed. Appl. 671: 299-317.
97. Bobeldijk, I., M. Hekman, J. de Vries-van der Weij, L. Coulier, R. Ramaker, R. Kleemann, T. Kooistra, C. Rubingh, A. Freidig, and E. Verheij. 2008. Quantitative profiling of bile acids in biofluids and tissues based on accurate mass high resolution LC-FT-MS: compound class targeting in a metabolomics workflow. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 871: 306-313.
98. Burkard, I., A. von Eckardstein, and K. M. Rentsch. 2005. Differentiated quantification of human bile acids in serum by high-performance liquid chromatography-tandem mass spectrometry. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 826: 147-159.
99. Ikegawa, S., T. Yanagihara, N. Murao, H. Watanabe, J. Goto, and T. Niwa. 1997. Separatory determination of bile acid 3-sulfates by liquid chromatography/electrospray ionization mass spectrometry. J. Mass Spectrom. 32: 401-407.
100. Goto, T., A. Shibata, D. Sasaki, N. Suzuki, T. Hishinuma, G. Kakiyama, T. Iida, N. Mano, and J. Goto. 2005. Identification of a novel conjugate in human urine: bile acid acyl galactosides. Steroids. 70: 185-192.
101. Goto, T., K. T. Myint, K. Sato, O. Wada, G. Kakiyama, T. Iida, T. Hishinuma, N. Mano, and J. Goto. 2007. LC/ESI-tandem mass spectrometric determination of bile acid 3-sulfates in human urine. 3beta-Sulfooxy-12alpha-hydroxy-5beta-cholanoic acid is an abundant nonamidated sulfate. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 846: 69-77.
102. Shinka, T., Y. Inoue, M. Ohse, and T. Kuhara. 2007. Simple and quantitative analysis of urinary sulfated tauro- and glycodihydroxycholic acids in infant with cholestasis by electrospray ionization mass spectrometry. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 855: 104-108.
103. Bootsma, A. H., H. Overmars, A. van Rooij, A. E. van Lint, R. J. Wanders, A. H. van Gennip, and P. Vreken. 1999. Rapid analysis of conjugated bile acids in plasma using electrospray tandem mass spectrometry: application for selective screening of peroxisomal disorders. J. Inherit. Metab. Dis. 22: 307-310.
104. Ando, M., T. Kaneko, R. Watanabe, S. Kikuchi, T. Goto, T. Iida, T. Hishinuma, N. Mano, and J. Goto. 2006. High sensitive analysis of rat serum bile acids by liquid chromatography/electrospray ionization tandem mass spectrometry. J. Pharm. Biomed. Anal. 40: 1179-1186.
105. Williams, R., E. M. Lenz, A. J. Wilson, J. Granger, I. D. Wilson, H. Major, C. Stumpf, and R. Plumb. 2006. A multi-analytical platform approach to the metabonomic analysis of plasma from normal and Zucker (fa/fa) obese rats. Mol. Biosyst. 2: 174-183.
106. Tessier, E., L. Neirinck, and Z. Zhu. 2003. High-performance liquid chromatographic mass spectrometric method for the determination of ursodeoxycholic acid and its glycine and taurine conjugates in human plasma. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 798: 295-302.
107. Ye, L., S. Liu, M. Wang, Y. Shao, and M. Ding. 2007. High-performance liquid chromatography-tandem mass spectrometry for the analysis of bile acid profiles in serum of women with intrahepatic cholestasis of pregnancy. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 860: 10-17.
108. Yang, L., A. Xiong, Y. He, Z. Wang, C. Wang, Z. Wang, W. Li, L. Yang, and Z. Hu. 2008. Bile acids metabonomic study on the CCl4- and alpha-naphthylisothiocyanate-induced animal models: quantitative analysis of 22 bile acids by ultraperformance liquid chromatography-mass spectrometry. Chem. Res. Toxicol. 21: 2280-2288.
109. Bentayeb, K., R. Batlle, C. Sanchez, C. Nerin, and C. Domeno. 2008. Determination of bile acids in human serum by on-line restricted access material-ultra high-performance liquid chromatography-mass spectrometry. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 869: 1-8.
110. Xiang, X., Y. Han, M. Neuvonen, M. K. Pasanen, A. Kalliokoski, J. T. Backman, J. Laitila, P. J. Neuvonen, and M. Niemi. 2009. Effect of SLCO1B1 polymorphism on the plasma concentrations of bile acids and bile acid synthesis marker in humans. Pharmacogenet. Genomics. 19: 447-457.
111. Perwaiz, S., B. Tuchweber, D. Mignault, T. Gilat, and I. M. Yousef. 2001. Determination of bile acids in biological fluids by liquid chromatography-electrospray tandem mass spectrometry. J. Lipid Res. 42: 114-119.
112. Plumb, R. S., P. D. Rainville, W. B. Potts III, K. A. Johnson, E. Gika, and I. D. Wilson. 2009. Application of ultra performance liquid chromatography-mass spectrometry to profiling rat and dog bile. J. Proteome Res. 8: 2495-2500.
113. Hamilton, J. P., G. Xie, J. P. Raufman, S. Hogan, T. L. Griffin, C. A. Packard, D. A. Chatfield, L. R. Hagey, J. H. Steinbach, and A. F. Hofmann. 2007. Human cecal bile acids: concentration and spectrum. Am. J. Physiol. Gastrointest. Liver Physiol. 293: G256-G263.
114. Hagio, M., M. Matsumoto, M. Fukushima, H. Hara, and S. Ishizuka. 2009. Improved analysis of bile acids in tissues and intestinal contents of rats using LC/ESI-MS. J. Lipid Res. 50: 173-180.
115. Ferdinandusse, S., S. Denis, P. L. Faust, and R. J. Wanders. 2009. Bile acids: role of peroxisomes. J. Lipid Res. 50: 2139-2147.
116. Parmentier, G. G., G. A. Janssen, E. A. Eggermont, and H. J. Eyssen. 1979. C27 bile acids in infants with coprostanic acidemia and occurrence of a 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-C29 dicarboxylic bile acid as a major component in their serum. Eur. J. Biochem. 102: 173-183.
117. Van Eldere, J. R., G. G. Parmentier, H. J. Eyssen, R. J. Wanders, R. B. Schutgens, J. Vamecq, F. Van Hoof, B. T. Poll-The, and J. M. Saudubray. 1987. Bile acids in peroxisomal disorders. Eur. J. Clin. Invest. 17: 386-390.
118. Johnson, D. W., H. J. ten Brink, R. C. Schuit, and C. Jakobs. 2001. Rapid and quantitative analysis of unconjugated C(27) bile acids in plasma and blood samples by tandem mass spectrometry. J. Lipid Res. 42: 9-16.
119. Lövgren-Sandblom, A., M. Heverin, H. Larsson, E. Lundström, J. Wahren, U. Diczfalusy, and I. Björkhem. 2007. Novel LC-MS/MS method for assay of 7alpha-hydroxy-4-cholesten-3-one in human plasma. Evidence for a significant extrahepatic metabolism. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 856: 15-19.
120. Honda, A., K. Yamashita, M. Numazawa, T. Ikegami, M. Doy, Y. Matsuzaki, and H. Miyazaki. 2007. Highly sensitive quantification of 7alpha-hydroxy-4-cholesten-3-one in human serum by LC-ESI-MS/MS. J. Lipid Res. 48: 458-464.
121. Honda, A., K. Yamashita, T. Hara, T. Ikegami, T. Miyazaki, M. Shirai, G. Xu, M. Numazawa, and Y. Matsuzaki. 2009. Highly sensitive quantification of key regulatory oxysterols in biological samples by LC-ESI-MS/MS. J. Lipid Res. 50: 350-357.
122. Lenz, E. M., R. E. Williams, J. Sidaway, B. W. Smith, R. S. Plumb, K. A. Johnson, P. Rainville, J. Shockcor, C. L. Stumpf, J. H. Granger, et al. 2007. The application of microbore UPLC/oa-TOF-MS and 1H NMR spectroscopy to the metabonomic analysis of rat urine following the intravenous administration of pravastatin. J. Pharm. Biomed. Anal. 44: 845-852.
123. Roda, A., F. Piazza, and M. Baraldini. 1998. Separation techniques for bile salts analysis. J. Chromatogr. B Biomed. Sci. Appl. 717: 263-278.
124. Sakakura, H., N. Kimura, H. Takeda, H. Komatsu, K. Ishizaki, and S. Nagata. 1998. Simultaneous determination of bile acids in rat liver tissue by high-performance liquid chromatography. J. Chromatogr. B Biomed. Sci. Appl. 718: 33-40.
125. Shimada, K., K. Mitamura, and T. Higashi. 2001. Gas chromatography and high-performance liquid chromatography of natural steroids. J. Chromatogr. A. 935: 141-172.
126. Rossi, S. S., J. L. Converse, and A. F. Hofmann. 1987. High pressure liquid chromatographic analysis of conjugated bile acids in human bile: simultaneous resolution of sulfated and unsulfated lithocholyl amidates and the common conjugated bile acids. J. Lipid Res. 28: 589-595.
127. Sakakura, H., M. Suzuki, N. Kimura, H. Takeda, S. Nagata, and M. Maeda. 1993. Simultaneous determination of bile acids in rat bile and serum by high-performance liquid chromatography. J. Chromatogr. A. 621: 123-131.
128. Roda, A., C. Cerre, P. Simoni, C. Polimeni, C. Vaccari, and A. Pistillo. 1992. Determination of free and amidated bile acids by high-performance liquid chromatography with evaporative light-scattering mass detection. J. Lipid Res. 33: 1393-1402.
129. Torchia, E. C., E. D. Labonte, and L. B. Agellon. 2001. Separation and quantitation of bile acids using an isocratic solvent system for high performance liquid chromatography coupled to an evaporative light scattering detector. Anal. Biochem. 298: 293-298.
130. Kakiyama, G., T. Iida, T. Goto, N. Mano, J. Goto, T. Nambara, L. R. Hagey, C. D. Schteingart, and A. F. Hofmann. 2006. Identification of a novel bile acid in swans, tree ducks, and geese: 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid. J. Lipid Res. 47: 1551-1558.
131. Kakiyama, G., A. Hosoda, T. Iida, Y. Fujimoto, T. Goto, N. Mano, J. Goto, and T. Nambara. 2006. A direct method for the separation and quantification of bile acid acyl glycosides by high-performance liquid chromatography with an evaporative light scattering detector. J. Chromatogr. A. 1125: 112-116.
132. Moschetta, A., F. Xu, L. R. Hagey, G. P. van Berge-Henegouwen, K. J. van Erpecum, J. F. Brouwers, J. C. Cohen, M. Bierman, H. H. Hobbs, J. H. Steinbach, et al. 2005. A phylogenetic survey of biliary lipids in vertebrates. J. Lipid Res. 46: 2221-2232.
133. Okuyama, S., N. Kokubunn, S. Higashidate, D. Uemura, and Y. Hirata. 1979. A new analytical method of individual bile acids using high-performance liquid chromatography and immobilized 3α-hydroxysteroid dehydrogenase in column form. Chem. Lett. 8: 1443-1446.
134. Björkhem, I., and O. Falk. 1983. Assay of the major bile acids in serum by isotope dilution-mass spectrometry. Scand. J. Clin. Lab. Invest. 43: 163-170.
135. Stellaard, F., and G. Paumgartner. 1987. Quantitation of serum bile acids by isotope dilution with 13C-labelled homologs. Clin. Chim. Acta. 162: 45-51.
136. Gatti, R., A. Roda, C. Cerre, D. Bonazzi, and V. Cavrini. 1997. HPLC-fluorescence determination of individual free and conjugated bile acids in human serum. Biomed. Chromatogr. 11: 11-15.
137. Kurosawa, T., H. Sato, M. Sato, H. Takechi, M. Machida, and M. Tohma. 1997. Analysis of stereoisomeric C27-bile acids by high performance liquid chromatography with fluorescence detection. J. Pharm. Biomed. Anal. 15: 1375-1382.
138. Budai, K., and N. B. Javitt. 1997. Bile acid analysis in biological fluids: a novel approach. J. Lipid Res. 38: 1906-1912.
139. Goto, J., T. Chikai, and T. Nambara. 1987. Studies on steroids. CCXXVII. Separation and determination of bile acid 7- and 12-sulphates in urine by high-performance liquid chromatography with fluorescence labelling. J. Chromatogr. A. 415: 45-52.
140. Karlaganis, G., and G. Paumgartner. 1979. Determination of bile acids in serum by capillary gas-liquid chromatography. Clin. Chim. Acta. 92: 19-26.
141. Huijghebaert, S. M., and A. F. Hofmann. 1986. Influence of the amino acid moiety on deconjugation of bile acid amidates by cholylglycine hydrolase or human fecal cultures. J. Lipid Res. 27: 742-752.
142. Batta, A. K., G. Salen, F. W. Cheng, and S. Shefer. 1979. Cleavage of the taurine conjugate of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid by rat fecal bacteria. J. Biol. Chem. 254: 11907-11909.
143. Batta, A. K., G. Salen, and S. Shefer. 1984. Substrate specificity of cholylglycine hydrolase for the hydrolysis of bile acid conjugates. J. Biol. Chem. 259: 15035-15039.
144. Hofmann, A. F., V. Loening-Baucke, J. E. Lavine, L. R. Hagey, J. H. Steinbach, C. A. Packard, T. L. Griffin, and D. A. Chatfield. 2008. Altered bile acid metabolism in childhood functional constipation: inactivation of secretory bile acids by sulfation in a subset of patients. J. Pediatr. Gastroenterol. Nutr. 47: 598-606.
145. Lepage, G., C. C. Roy, and A. M. Weber. 1981. Separation of sulfated from non-sulfated serum bile acids without the use of Sephadex columns. J. Lipid Res. 22: 705-711.
146. Dayal, B., and N. H. Ertel. 1998. Rapid hydrolysis of bile acid conjugates using microwaves: retention of absolute stereochemistry in the hydrolysis of (25R) 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oyltaurine. Lipids. 33: 333-338.
147. Huijghebaert, S., G. Parmentier, and H. Eyssen. 1984. Specificity of bile salt sulfatase activity in man, mouse and rat intestinal microflora. J. Steroid Biochem. 20: 907-912.
148. Hirano, Y., H. Miyazaki, S. Higashidate, and F. Nakayama. 1987. Analysis
149. Princen, H. M., P. Meijer, and F. Kuipers. 1990. One-step solvolysis of 3-, 7- and 12-sulfated free and conjugated bile acids. Clin. Chim. Acta. 192: 77-83.
150. Parmentier, G., and H. Eyssen. 1975. Synthesis of the specific monosulfates of cholic acid. Steroids. 26: 721-729.
151. Almé, B., and J. Sjövall. 1980. Analysis of bile acid glucuronides in urine. Identification of 3 alpha, 6 alpha, 12 alpha-trihydroxy-5 beta-cholanoic acid. J. Steroid Biochem. 13: 907-916.
152. Momose, T., J. Maruyama, T. Iida, J. Goto, and T. Nambara. 1997. Comparative abilities and optimal conditions for beta-glycosidase enzymes to hydrolyse the glucuronide, glucoside, and N-acetylglucosaminide conjugates of bile acids. Biol. Pharm. Bull. 20: 828-833.
153. Child, P., M. Aloe, and D. Mee. 1987. Separation and quantitation of fatty acids, sterols and bile acids in feces by gas chromatography as the butyl ester-acetate derivatives. J. Chromatogr. A. 415: 13-26.
154. Batta, A. K., G. Salen, K. R. Rapole, M. Batta, D. Earnest, and D. Alberts. 1998. Capillary gas chromatographic analysis of serum bile acids as the n-butyl ester-trimethylsilyl ether derivatives. J. Chromatogr. B Biomed. Sci. Appl. 706: 337-341.
155. Batta, A. K., G. Salen, P. Batta, G. S. Tint, D. S. Alberts, and D. L. Earnest. 2002. Simultaneous quantitation of fatty acids, sterols and bile acids in human stool by capillary gas-liquid chromatography. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 775: 153-161.
156. Batta, A. K., G. Salen, M. Batta, D. Earnest, and D. Alberts. 1997. Capillary gas-liquid chromatography of acetate-methyl esters of bile acids. J. Chromatogr. A. 766: 286-291.
157. Sjövall, J., A. M. Lawson, and K. D. Setchell. (1985) Mass spectrometry of bile acids. In Methods in Enzymology. J. H. Law and H. C. Rilling, editors. Academic Press, London. 63-113.
158. Setchell, K. D., and A. M. Lawson. (1989) Bile acids. In Mass Spectrometry. Clinical Biochemistry-Principles, Methods, Applications. A. M. Lawson, editor. Walter de Gruyter, Berlin, New York. 54-125.
159. Miyazaki, H., M. Ishibashi, and K. Yamashita. 1978. Use of a new silylating agent for separation of bile acids and cholesterol by selected ion monitoring with the computer controlled intensity matching technique. Biomed. Mass Spectrom. 5: 469-476.
160. Evershed, R. P. (1993) Advances in silylation. In Handbook of Derivatives for Chromatography. K. Blau and J. M. Halket, editors. Wiley, London. 52-108.
161. Kimura, A., M. Suzuki, T. Murai, T. Inoue, H. Kato, D. Hori, Y. Nomura, T. Yoshimura, T. Kurosawa, and M. Tohma. 1997. Perinatal bile acid metabolism: analysis of urinary bile acids in pregnant women and newborns. J. Lipid Res. 38: 1954-1962.
162. Thenot, J-P., and E. C. Horning. 1972. MO-TMS derivatives of human urinary steroids for GC and GC-MS studies. Anal. Lett. 5: 21-33.
163. Shoda, J., M. Axelson, and J. Sjövall. 1993. Synthesis of potential C27-intermediates in bile acid biosynthesis and their deuterium-labeled analogs. Steroids. 58: 119-125.
164. Batta, A. K., S. K. Aggarwal, G. S. Tint, M. Batta, and G. Salen. 1995. Capillary gas-liquid chromatography of 6-hydroxylated bile acids. J. Chromatogr. A. 704: 228-233.
165. Batta, A. K., and G. Salen. 1999. Gas chromatography of bile acids. J. Chromatogr. B Biomed. Sci. Appl. 723: 1-16.
166. Dumaswala, R., K. D. Setchell, L. Zimmer-Nechemias, T. Iida, J. Goto, and T. Nambara. 1989. Identification of 3 alpha,4 beta,7 alpha-trihydroxy-5 beta-cholanoic acid in human bile: reflection of a new pathway in bile acid metabolism in humans. J. Lipid Res. 30: 847-856.
167. Iida, T., F. C. Chang, T. Matsumoto, and T. Tamura. 1983. Separation of mono-, di-, and trihydroxy stereoisomers of bile acids by capillary gas-liquid chromatography. J. Lipid Res. 24: 211-215.
168. Iida, T., I. Komatsubara, F. C. Chang, J. Goto, and T. Nambara. 1990. Capillary gas liquid chromatographic separation of oxo and oxo-hydroxy bile acid isomers of allo and normal series. Lipids. 25: 753-755.
169. Iida, T., I. Komatsubara, F. C. Chang, J. Goto, and T. Nambara. 1991. Capillary gas chromatographic separation of stereoisomeric bile acids with vicinal glycol structure by "mixed" alkylboronate derivatives. J. Chromatogr. A. 537: 345-356.
170. Lawson, A. M., and K. D. Setchell. (1988) Appendix. In The Bile Acids. Volume 4: Methods and Applications. K. D. Setchell, D. Kritchevsky, and P. P. Nair, editors. Plenum Press, New York. 571-575.
171. Shoda, J., T. Osuga, R. Mahara, M. Tohma, K. Matsuura, N. Tanaka, Y. Matsuzaki, and H. Miyazaki. 1989. Altered metabolism of bile acids in cholestasis: determination of 1 beta- and 6 alpha-hydroxylated metabolites. J. Chromatogr. A. 488: 315-328.
172. Batta, A. K., S. K. Aggarwal, R. Mirchandani, S. Shefer, and G. Salen. 1992. Capillary gas-liquid chromatographic separation of bile alcohols. J. Lipid Res. 33: 1403-1407.
173. Iida, T., M. Hikosaka, J. Goto, and T. Nambara. 2001. Capillary gas chromatographic behaviour of tert.-hydroxylated steroids by trialkylsilylation. J. Chromatogr. A. 937: 97-105.
174. Shan, H., J. Pang, S. Li, T. B. Chiang, W. K. Wilson, and G. J. Schroepfer, Jr. 2003. Chromatographic behavior of oxygenated derivatives of cholesterol. Steroids. 68: 221-233.
175. Lawson, A. M., and K. D. Setchell. (1988) Mass spectrometry of bile acids. In The Bile Acids. Volume 4: Methods and Applications. K. D. Setchell, D. Kritchevsky, and P. P. Nair, editors. Plenum Press, New York. 167-268.
176. Sjövall, J., W. J. Griffiths, K. D. Setchell, N. Mano, and J. Goto. (2009) Analysis of bile acids, In Steroid Analysis, 2nd edition. H. L. J. Makin and D. B. Gower, editors. Springer. In press.
177. Little, J. M., P. Zimniak, A. Radominska, and R. Lester. 1987. Hyodeoxycholate-6-O-glucuronide cannot be quantitated with 3 alpha-hydroxysteroid dehydrogenase. J. Lipid Res. 28: 1370-1372.
178. Porter, J. L., J. S. Fordtran, C. A. Santa Ana, M. Emmett, L. R. Hagey, E. A. Macdonald, and A. F. Hofmann. 2003. Accurate enzymatic measurement of fecal bile acids in patients with malabsorption. J. Lab. Clin. Med. 141: 411-418.
179. Danielsson, H., P. Eneroth, K. Hellström, S. Lindstedt, and J. Sjövall. 1963. On the turnover and excretory products of cholic and chenodeoxycholic acid in man. J. Biol. Chem. 238: 2299-2304.
180. Kobayashi, N., H. Oiwa, and J. Goto. 1998. Production and characterization of group-specific monoclonal antibodies recognizing nonamidated, glycine- and taurine-amidated ursodeoxycholic acid 7-N-acetylglucosaminides. J. Steroid Biochem. Mol. Biol. 64: 171-177.
181. Kobayashi, N., H. Katsumata, H. Katayama, H. Oiwa, J. Goto, and Y. Takeuchi. 2000. A monoclonal antibody-based enzyme-linked immunosorbent assay of ursodeoxycholic acid 3-sulfates in human urine. J. Steroid Biochem. Mol. Biol. 72: 265-272.
182. Kobayashi, N., H. Katsumata, Y. Uto, J. Goto, T. Niwa, K. Kobayashi, and Y. Mizuuchi. 2002. A monoclonal antibody-based enzyme-linked immunosorbent assay of glycolithocholic acid sulfate in human urine for liver function test. Steroids. 67: 827-833.