title: Testosterone decreases 3beta-hydroxysteroid dehydrogenase-isomerase messenger ribonucleic acid in cultured mouse Leydig cells by a strain-specific mechanism.
abstract: We previously reported a strain-related difference in basal 3beta-hydroxysteroid dehydrogenase-isomerase (3betaHSD) activity in response to testosterone in cultured Leydig cells. The data suggested that the response to testosterone was androgen receptor mediated and that testosterone was acting via a trans-acting factor distal to the androgen receptor to regulate Leydig cell basal 3betaHSD activity. This study was designed to determine whether the previous reported strain-related difference in basal 3betaHSD activity in response to testosterone was due to a difference at the 3betaHSD protein and/or at the mRNA level. In C57BL/6J Leydig cells, 2.0 microM testosterone significantly decreased basal 3betaHSD immunoreactive mass by day 6 in culture. Treatment with 2.0 microM testosterone and 2.0 microM hydroxyflutamide, an androgen receptor antagonist, negated the inhibitory effect of testosterone on C57BL/6J 3betaHSD immunoreactive mass. Treatment with 2.0 microM testosterone also significantly decreased 3betaHSD mRNA content in C57BL/6J Leydig cells, which was detectable on day 3 in culture. In contrast to Leydig cells from C57BL/6J mice, Leydig cells from C3H/HeJ mice were not susceptible to the inhibitory effect of testosterone on 3betaHSD. Treatment with 2.0 microM testosterone had no detectable effect on C3H/HeJ 3betaHSD immunoreactive mass or mRNA content at any time point in culture. These data indicate that the testosterone-induced loss of basal 3betaHSD activity in C57BL/6J Leydig cells can be accounted for by the loss of 3betaHSD immunoreactive mass, which is preceded by the loss of 3betaHSD mRNA, and that the strain-related difference in the regulation of 3betaHSD is present at all three levels. Thus, the putative trans-acting factor involved in the mechanism whereby testosterone decreases basal 3betaHSD is likely to regulate the amount of 3betaHSD mRNA.
authors.affiliation: Department of Biological Sciences, Kent State University, Ohio 44242, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Heggland
authors.forename: S A
authors.initials: SA
authors.lastname: Signs
authors.forename: J R
authors.initials: JR
authors.lastname: Stalvey
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D007985:Leydig Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009097:Multienzyme Complexes / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D011375:Progesterone Reductase / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D013251:Steroid Isomerases / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*
chemical_list: C021425:3 beta-hydroxysteroid oxidoreductase-delta(5) 3-ketosteroid isomerase; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D013739:Testosterone; D011375:Progesterone Reductase; D013251:Steroid Isomerases