Alternate hydroxylating activities in newborn rat adrenal cells in primary culture.
During the course of a study to produce reference compounds, the metabolism of tetrahydrogenated derivatives (ring A reduced) of progesterone, 6 alpha-hydroxyprogesterone, 11-deoxycorticosterone and corticosterone in newborn rat adrenal cells in primary culture was studied. Analysis of the metabolites was made by gas chromatography-mass spectrometry. Most products resulted from the enzymatic reactions of 11 beta-, 18- and 21-hydroxylation, reduction of the 20-oxo group and oxidoreduction of the 3-hydroxyl group. However, unexpected metabolites were produced from the incubation of 3 beta, 5 alpha-tetrahydroprogesterone and 6 alpha-hydroxy-3 alpha, 5 beta-tetrahydroprogesterone. They resulted from the 16 alpha-hydroxylation of the precursors and probably from the 15 alpha-, 16 beta- and 17 alpha-hydroxylation of 6 alpha-hydroxy-3 alpha, 5 beta-tetrahydroprogesterone. These hydroxylating activities are weak and were not detected from the endogenous steroidogenesis. They were not detected either from the incubation of exogenous steroids with a 3-oxo-4-ene structure or from steroids with a 21-hydroxyl substituent. They result only from substrates showing diminished or no affinity towards the 11 beta/18- and 21-steroid hydroxylase systems. These unusual hydroxylations could be catalyzed by monooxygenase systems in the endoplasmic reticulum similar to those present in the liver or by the monooxygenase systems specific to steroidogenesis. In particular, the reaction specificity of cytochrome P-450(11) beta could be altered by the presence of a 6 alpha-hydroxyl group in a tetrahydrogenated steroid.
Laboratoire de Biochimie des Interactions Cellulaires, Faculté des Sciences, Université de Dijon, France.
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Bournot
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Ramirez
D000311:Adrenal Glands / Q000201:enzymology / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001189:Aryl Hydrocarbon Hydroxylases; D002478:Cells, Cultured; D002855:Chromatography, Thin Layer; D003345:Corticosterone / Q000378:metabolism; D000072467:Cytochrome P450 Family 2; D003900:Desoxycorticosterone / Q000031:analogs & derivatives; D008401:Gas Chromatography-Mass Spectrometry; D006900:Hydroxylation; D006908:Hydroxyprogesterones / Q000378:metabolism; D011374:Progesterone / Q000031:analogs & derivatives; D051381:Rats; D039181:Steroid 16-alpha-Hydroxylase
D006908:Hydroxyprogesterones; D003900:Desoxycorticosterone; D011374:Progesterone; D001189:Aryl Hydrocarbon Hydroxylases; C450279:CYP2C11 protein, rat; D000072467:Cytochrome P450 Family 2; D039181:Steroid 16-alpha-Hydroxylase; D003345:Corticosterone