Variation of the pituitary response to LH-releasing hormone (LH-RH) during a 24-hour period in male, diestrous female and androgenized female rats.
The pituitary response to LH-RH was studied at 8 a.m., 4 p.m. and 12 p.m. in normal male rats, female rats on day 1 of diestrus and female rats injected with testosterone propionate on the 2nd day of life. Androgenized rats responded to LH-RH with a greater release of LH than did female diestrous and male rats. In the 3 groups the lowest response to LH-RH was observed at 12 p.m., and the highest at 8 a.m., with the exception of androgenized rats which responded with a similar magnitude of LH release at 8 a.m. and 4 p.m. The release of FSH after the injection of LH-RH was studied only at 4 p.m. and only normal male rats responded with a significant FSH release.
D000818:Animals; D004347:Drug Interactions; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects*; D011247:Pregnancy; D051381:Rats; D013739:Testosterone / Q000494:pharmacology*; D013997:Time Factors
D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone