Between-ovary interaction in the regulation of follicle growth, corpus luteum function, and gonadotropin secretion in the primate ovarian cycle. III. Temporal and spatial dissociation of folliculogenesis and negative feedback regulation of tonic gonadotropin release after luteectomy in rhesus monkeys.
This study was designed to examine effects of previous ovarian status on subsequent follicle growth and the role of between-ovary communication in the regulation of folliculogenesis and gonadotropin secretion during the primate ovarian cycle. Responses to luteectomy were compared in two groups of rhesus monkeys. In the first, follicle growth and corpus luteum function had been constrained chronically to a single ovary by hemiovariectomy performed 66--258 days earlier; the second group was composed of intact monkeys that underwent contralateral wedge resection at luteectomy. In each group, luteal ablation was followed by a prompt fall in serum progesterone levels, a premature onset of menses, and the next preovulatory gonadotropin surges 14.7 +/- 1.1 or 15.4 +/- 1.4 days later (mean +/- SE; P greater than 0.25). Although the patterns of circulating estradiol before and after ablation in each group were superimposable, luteectomy in monkeys lacking a contralateral ovary was followed by a large (2- to 4-fold) and prolonged (7--10 days) increase in serum FSH, whereas in monkeys with two ovaries, serum FSH levels exhibited only a small short-lived rise. The findings indicate that 1) prior chronic constraint of ovarian function to a single ovary did not alter the overall time course of new follicle growth culminating in ovulation after luteectomy; 2) the contralateral ovary provided the principal negative feedback regulation of gonadotropin secretion for some time after luteectomy even though it may not have been the exclusive site of new follicle growth; 3) whereas the ability of the luteectomized ovary to regulate tonic gonadotropin secretion was temporarily impaired, its ability to support the customary temporal pattern of follicle growth after luteal ablation was not; 4) some (contralateral) ovarian factor other than estradiol or progesterone apparently made a major contribution to the regulation of FSH secretion after luteectomy; and 5) folliculogenesis culminating in ovulation from a single follicle and the negative feedback regulation of tonic gonadotropin secretion in some circumstances may occur concurrently but separately on opposite ovaries or may occur at different times within the same ovary.
D000818:Animals; D002369:Castration; D003338:Corpus Luteum / Q000502:physiology* / Q000601:surgery; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D000882:Haplorhini; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism*; D008253:Macaca mulatta; D008598:Menstruation; D010053:Ovary / Q000502:physiology*; D010060:Ovulation
D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone