title: Co-induction of 17 alpha-hydroxylase and C-17,20-lyase activities in primary cultures of bovine adrenocortical cells in response to ACTH treatment.
abstract: Bovine adrenocortical cells in primary culture were used to examine the trophic effect of ACTH on the induction of the 17 alpha-hydroxylase and C-17,20-lyase activities. The addition of exogenous pregnenolone to bovine adrenal microsomes showed the appearance of 17 alpha-hydroxy-pregnenolone before the formation of dehydroepiandrosterone. The same sequence of activities was evident in postmitochondrial supernate from bovine adrenocortical cells cultured 36 h in the presence of 1 microM ACTH but not in postmitochondrial supernate from control cells. In another study, bovine adrenocortical cells were cultured for 36 h after which 30 microM 17 alpha-hydroxypregnenolone was added to the medium and the incubation continued 1 h; there was a 4-fold increase in androgen content in the media from ACTH-treated cells over controls. Measurement of the 17 alpha-hydroxylase and C-17,20-lyase reactions in postmitochondrial supernate from cells cultured 0-72 h in the presence of ACTH or 1 mM dibutyryl cAMP showed concomitant increases in the two activities and both activities were inhibited by the same compounds known to inhibit 17 alpha-hydroxylase activity. These observations support the concept of the co-induction of 17 alpha-hydroxylase and C-17,20-lyase activities in response to ACTH; results in keeping with previous studies indicating that the two activities are catalyzed by a single gene product, the polypeptide chain P-45017a.
authors.affiliation: Department of Biology, Southern Methodist University, Dallas, TX 75275.
authors.forename: J L
authors.initials: JL
authors.lastname: McCarthy
authors.forename: M R
authors.initials: MR
authors.lastname: Waterman
mesh_terms: D006907:17-alpha-Hydroxypregnenolone / Q000096:biosynthesis / Q000494:pharmacology; D000302:Adrenal Cortex / Q000187:drug effects / Q000201:enzymology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000446:Aldehyde-Lyases / Q000096:biosynthesis*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D003687:Dehydroepiandrosterone / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D011284:Pregnenolone / Q000494:pharmacology; D013254:Steroid 17-alpha-Hydroxylase / Q000096:biosynthesis*; D013250:Steroid Hydroxylases / Q000096:biosynthesis*
chemical_list: D006907:17-alpha-Hydroxypregnenolone; D003687:Dehydroepiandrosterone; D003994:Bucladesine; D011284:Pregnenolone; D000324:Adrenocorticotropic Hormone; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D013254:Steroid 17-alpha-Hydroxylase; D000446:Aldehyde-Lyases