Changes of hypothalamic LH-RF content during the rat estrous cycle.
Anti-LH-RF serum was produced in rabbits by synthetic LH-RF-BSA conjugate prepard with bis-diazotized benzidine. Employing this antiserum, a radioimmunoassay for LH-RF was established with the assay range from 0.8 to 10 ng/ml. Acid extracts of hypothalami from 4 day cycling rats through various stages of the estrous cycle particularly in the afternoon of proestrus were measured for their LH-RF contents. The hypothalamic LH-RF content was high at 10:00 on the day of proestrus and declined until 17:00 and thereafter, the content gradually increased to reach the basal level. Serum LH showed the highest level at 17:00 on the day of proestrus and fell at 21:00 on the same day. Accompaning this change of serum LH level, pituitary LH content began to decrease at 17:00 of proestrus. These results indicate that LH-RF released in the afternoon of proestrus may participiate to stimulate the preovulatory discharge of LH in the rat.
D000818:Animals; D002940:Circadian Rhythm; D004967:Estrogens / Q000494:pharmacology; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism* / Q000494:pharmacology; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010053:Ovary / Q000502:physiology; D010902:Pituitary Gland / Q000378:metabolism; D011247:Pregnancy; D011359:Proestrus; D011374:Progesterone / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats
D004967:Estrogens; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D007986:Luteinizing Hormone