Increased 21-hydroxylase and shutdown of C(17,20) lyase activities in testicular tissues of the grouper (Epinephelus coioides) during 17alpha-methyltestosterone-induced sex inversion.
The metabolism in vitro of [(3)H]17-hydroxyprogesterone by gonadal tissues of the grouper (Epinephelus coioides) during 17alpha-methyltestosterone (MT)-induced female-to-male sex inversion was examined. In the female phase, C(17,20) lyase, 5beta-reductase, 3alpha/beta-HSD, 20beta-HSD, and 17beta-HSD activities resulted in the biosynthesis of 5beta-pregnans and 5beta-androstanes (including 5beta-androstane-3alpha/beta, 17beta-diol, 3alpha/beta, 17alpha-dihydroxy-5beta-pregnen-20-one, and 5beta-androstane-3,17-dione). In the MT-induced male phase, however, the abrogation of C(17,20) lyase activity and the concomitant activation of 21alpha-hydroxylase/11beta-hydroxylase resulted in the preferential synthesis of polar 21alpha-hydroxlyated 5beta-pregnans (5beta-pregnan-3beta,17alpha,20beta,21alpha-tetrol and 3beta,20beta,21alpha-trihydroxy-5beta-pregnan-3-one) and corticosteroids (11-deoxycortisol and cortisol). Interestingly, synthesis of these 21alpha-hydroxylated 5beta-pregnans and corticosteroids was uniquely compartmentalized in only testicular tissues of the MT-induced males. This study shows that there is selective activation of specific steroidogenic enzymes in the different sexual phases leading to the synthesis of metabolites that may be involved in regulating sex inversion of the grouper.
Lee
S T
ST
Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
Lam
T J
TJ
Tan
C H
CH
D019326:17-alpha-Hydroxyprogesterone / Q000378:metabolism; D000731:Androstanes / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005260:Female; D057850:Hermaphroditic Organisms; D008297:Male; D008777:Methyltestosterone / Q000494:pharmacology*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D010473:Perciformes / Q000502:physiology*; D011278:Pregnanes / Q000378:metabolism; D019849:Sex Determination Processes; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism*; D013255:Steroid 21-Hydroxylase / Q000378:metabolism*; D013737:Testis / Q000187:drug effects / Q000201:enzymology*
D000731:Androstanes; D011278:Pregnanes; D019326:17-alpha-Hydroxyprogesterone; D013255:Steroid 21-Hydroxylase; D013254:Steroid 17-alpha-Hydroxylase; D008777:Methyltestosterone