Effects of testosterone on gonadotrophin responses to synthetic LH and FSH releasing hormone (LRH) in normal men.
LRH tests were performed in 6 adult men with intravenous injections of 25 mug, before and one week after an intramuscular injection of 250 mg testosterone oenanthate (Testoviron Depot). One week after intramuscular injection of Testoviron the tonic secretion of LH was completely suppressed, but the reactivity or the reserve capacity of LH secretion, as tested by LRH, remained unchanged. In contrast, the tonic secretion of FSH and the reactivity of FSH secretion to LRH were both partly suppressed. Three months after the Testoviron injection, the basal levels of LH were still significantly lower than the control values, but the basal levels of FSH were identical to the control values. These data indicate that, in man, the feedback action of testosterone on gonadotrophin secretion could be exerted, at least for LH, at the hypothalamic level rather than at the pituitary level . No significant effects of LRH were noted on the circulating levels of growth hormone and sugar. There was a distinct rise in serum prolactin, which was occasionally significant, within 30 min after LRH injection; this is considered to be without physiological significance.
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage; D006065:Gonadotropins, Pituitary / Q000097:blood / Q000378:metabolism*; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D011388:Prolactin / Q000097:blood / Q000378:metabolism; D012636:Secretory Rate / Q000187:drug effects; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology*
D001786:Blood Glucose; D006065:Gonadotropins, Pituitary; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone