Between-Ovary Interaction in the Regulation of Follicle Growth, Corpus Luteum Function, and Gonadotropin Secretion in the Primate Ovarian Cycle. II. Effects of Luteectomy and Hemiovariectomy during the Luteal Phase in Cynomolgus Monkeys

Abstract

To examine the role of between-ovary interaction in the regulation of folliculogenesis in the primate ovarian cycle, the active corpus luteum was ablated on days 16–19 to interrupt the menstrual cycle, and one ovary was removed concurrently to restrict the locus of new follicle growth. Ablation of the corpus luteum, alone or along with the ipsi- or contralateral ovary, elicited stereotypical responses; the cycle in progress was terminated and the next preovulatory gonadotropin surges occurred about 2 weeks after luteectomy. Ablation of the contralateral ovary alone had no manifest effect. The findings indicate that 1) in cynomolgus monkeys, as in rhesus, since luteectomy advanced the next ovulation, follicle growth was arrested in the presence of the active corpus luteum and resumed soon after its extirpation; 2) the time course of new follicle growth culminating in ovulation after luteectomy was not affected by the concurrent removal of one ovary or the concomitant restriction of the locus of new follicle growth; 3) the next follicle destined to ovulate was not selected until after removal of the corpus luteum; 4) since the interval from luteectomy to the next LH surge was not different from the corresponding interval after follicle cautery, the ovarian hormonal milieu prevailing at ablation had no discernible differential effects on the time course of new follicle growth; 5) in the presence of the active corpus luteum, the contralateral ovary contributes little, if at all, to the regulation of gonadotropin secretion or to the function and lifespan of the corpus luteum; 6) the suppressive action of the corpus luteum is not limited to follicles of the ipsilateral ovary but extends, in some manner, to follicles of the contralateral ovary as well; and 7) unlike bilateral ovulators, a compensatory rise in gonadotropins after unilateral ovariectomy in this primate is conditional on the ovary removed and the surety of the active corpus luteum.