Effect of chronic ethanol feeding on testicular content of enzymes required for testosteronogenesis.
Ethanol is a known inducer of microsomal enzymes as well as a testicular toxin. In order to evaluate the effect of chronic ethanol ingestion upon the microsomal enzymes required for testosterone synthesis, we examined the activity of four testicular enzymes (3 beta-hydroxysteroid dehydrogenase/isomerase, 17 alpha-hydroxylase, 17,20-lyase, and 17 beta-hydroxysteroid dehydrogenase) in 14 pairs of adult chronic alcohol-fed rats and their age-matched isocaloric controls. Ethanol feeding enhanced the activity of 17,20-lyase when expressed as either activity/mg of protein (p less than 0.05) or activity/g of testis (P less than 0.025). Similarly, the activity of 17 alpha-hydroxylase was increased in testes of the alcohol-fed animals (p less than 0.025) compared to controls. In contrast, chronic ethanol feeding reduced total activity of 3 beta-hydroxysteroid dehydrogenase/isomerase in alcohol-fed animals (p less than 0.05) compared to controls. No effect of ethanol feeding was seen on activity of 17 beta-hydroxysteroid dehydrogenase. Based upon these studies we conclude that chronic ethanol ingestion (1) increases testicular 17 alpha-hydroxylase and 17,20-lyase and (2) reduces 3 beta-hydroxysteroid dehydrogenase/isomerase in rat testicular microsomes. Therefore, we would propose that the major effect of chronic ethanol ingestion upon the enzymes required for testosterogenesis is the reduction of 3 beta-hydroxysteroid dehydrogenase/isomerase activity, the rate limiting step in sex steroid production from pregnenolone.
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000437:Alcoholism / Q000201:enzymology*; D000446:Aldehyde-Lyases / Q000378:metabolism; D000818:Animals; D004032:Diet; D006801:Humans; D006908:Hydroxyprogesterones / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D011284:Pregnenolone / Q000378:metabolism; D051381:Rats; D013254:Steroid 17-alpha-Hydroxylase; D013737:Testis / Q000201:enzymology*; D013739:Testosterone / Q000096:biosynthesis*
D006908:Hydroxyprogesterones; D013739:Testosterone; D011284:Pregnenolone; D007986:Luteinizing Hormone; D015067:17-Hydroxysteroid Dehydrogenases; D015096:3-Hydroxysteroid Dehydrogenases; D013254:Steroid 17-alpha-Hydroxylase; D000446:Aldehyde-Lyases