Effects of active and passive immunization with LH-RH on gonadotrophin secretion and reproductive function in female rats.
In order to get information about the physiological role played by LH-RH in the regulation of tonic and phasic secretion of gonadotrophins, and about the existence of FSH-RH distinct from LH-RH, we attempted to neutralize endogenous LH-RH by passive and active immunization with LH-RH in female rats. Anti-LH-RH serum prevented pre-ovulatory gonadotrophin surges at proestrus and ovulation, and it suppressed gonadotrophin increase induced by oestradiol benzoate or progesterone in ovariectomized rats. Elevated serum gonadotrophin concentrations in long-term ovariectomized rats were lowered by anti-LH-RH serum injection. The decrease in FSH levels was less than that in LH levels. Serum FSH rose without significant changes in serum LH level for 6 h after ovariectomy on pro-oestrus or dioestrus. The post-ovariectomy rise of FSH was not suppressed by the anti-LH-RH serum which was enought to inhibit serum LH to undetectable levels. Active immunization with LH-RH resulted in decreasing LH levels but failed to alter FSH levels in both serum and pituitary. Seven out of 10 rats immunized with LH-RH became constantly di-oestrous. The weights of anterior pituitary, ovary and uterus of the LH-RH immunized rats were significantly smaller than those of BSA immunized controls. Ovaries of LH-RH immunized rats contained few fresh corpora lutea. These results indicate that LH-RH plays a significant role in the control of both plastic and tonic secretion of LH and FSH. The existence of FSH-RH distinct from LH-RH or mechanism which specially controls the basal FSH secretion is indicated.
D000818:Animals; D001666:Binding Sites, Antibody; D002369:Castration; D004958:Estradiol / Q000494:pharmacology; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology / Q000502:physiology*; D007106:Immune Sera; D007114:Immunization; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010053:Ovary / Q000187:drug effects; D010903:Pituitary Gland, Anterior / Q000187:drug effects; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D013997:Time Factors; D014599:Uterus / Q000187:drug effects
D007106:Immune Sera; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone