Effects of age and 1,4,6-androstatriene-3,17-dione on activities of hCG-induced 19-hydroxylase and aromatase of rat testes.
The testicular aromatase activity was significantly increased by administration of hCG to 18-day old rats, but not increased in 29-day old rats. 1,4,6-Androstatriene-3,17-dione did not inhibit the in vitro conversion of testosterone to 19-hydroxytestosterone by the testicular cell-free homogenates of the hCG-treated 18-day old rats, but strongly suppressed production of estrogen from 19-hydroxyandrostenedione. On the other hand, the 19-hydroxylase activity of 18-day old rats stimulated by hCG was reduced to about 50% of the control value by SKF-525A, SU-4,885, SU-8,000 and SU-9,055 at their concentration of 10(-4) M. From our results, it is postulated that there are two distinct steps in the process of aromatization of testosterone, the one, the primary 19-hydroxylation which is inhibited by SKF-525A and SU-compounds, but not by 1,4,6-androstatriene-3,17-dione, and the other, aromatization of 19-hydroxylated androgen which is inhibited by both 1,4,6-androstatriene-3,17-dione and non-steroidal inhibitors.
D000375:Aging; D000733:Androstatrienes / Q000494:pharmacology*; D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010088:Oxidoreductases / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D051381:Rats; D011919:Rats, Inbred Strains; D013250:Steroid Hydroxylases / Q000378:metabolism*; D013737:Testis / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D014316:Tritium
D000733:Androstatrienes; D006063:Chorionic Gonadotropin; D014316:Tritium; C011658:androsta-1,4,6-triene-3,17-dione; D010088:Oxidoreductases; D013250:Steroid Hydroxylases; C027110:steroid 19-hydroxylase; D001141:Aromatase