title: Characteristics of the inhibitory effect of chronic treatment with an LHRH agonist on testicular steroidogenesis in the dog.
abstract: Daily subcutaneous administration for 3 months of the potent LHRH agonist (D-Ser(TBU)6, des-Gly-NH2(10] LHRH ethylamide (25 micrograms) to adult dogs having spontaneous benign prostate hyperplasia (BPH) causes a marked inhibition of testicular androstenedione and testosterone secretion. This inhibition of delta 4-androgen secretion is accompanied by a decrease of testicular progestin precursors and 5 alpha-androgen metabolites, thus suggesting that, in dog, the loss of testicular steroidogenic activity, induced by the administration of an LHRH agonist, is due to a total inhibition of testicular steroidogenesis. In plasma, the concentration of both testosterone and dihydrotestosterone is also markedly depressed while androstane-3 alpha, 17 beta-diol levels remain unchanged. Measurement of prostatic steroid content has shown that administration of the LHRH agonist as well as castration is associated with a marked decrease in androstenedione, testosterone, and dihydrotestosterone levels in prostate while there is a small inhibition of androst-5-ene-3 beta, 17 beta-diol, androstane-3 beta, 17 beta-diol, dehydroepiandrosterone, and estrone concentrations in this tissue. The present data show that treatment with an LHRH agonist in the dog causes a marked inhibition of testicular steroid secretion similar to the one observed in adult men, and suggest that steroids from adrenal origin may also be involved in prostatic function.
mesh_terms: D019326:17-alpha-Hydroxyprogesterone; D000728:Androgens / Q000096:biosynthesis*; D000735:Androstenedione / Q000096:biosynthesis; D000818:Animals; D002064:Buserelin / Q000494:pharmacology*; D002369:Castration; D013196:Dihydrotestosterone / Q000097:blood; D004285:Dogs; D004967:Estrogens / Q000096:biosynthesis*; D006908:Hydroxyprogesterones / Q000096:biosynthesis; D008297:Male; D011374:Progesterone / Q000096:biosynthesis*; D011470:Prostatic Hyperplasia / Q000378:metabolism*; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis / Q000097:blood
chemical_list: D000728:Androgens; D004967:Estrogens; D006908:Hydroxyprogesterones; D013196:Dihydrotestosterone; D013739:Testosterone; D000735:Androstenedione; D011374:Progesterone; D019326:17-alpha-Hydroxyprogesterone; D002064:Buserelin