Regulation of luteal activity in neonatally castrated male rats bearing ovarian cysts.

Abstract

The regulation of luteal activity was studied in neonatally castrated male rats (NC—males) bearing ovarian and vaginal grafts. In R—strain NC—males luteal phases of about 26 days occurred spontaneously. In 5–day cyclic (R X V)FX hybrid NC—males bearing ectopically grafted pituitary tissue, series of consecutive luteal periods of 14–30 days duration were observed. In order to induce a luteal phase of 27–31 days the presence of an ectopic pituitary graft for only 6–10 days following ovulation was sufficient. Luteal activity could also be induced by electrical stimulation of the ventromedial hypothalamus on the day of ovulation. A single injection of 2.5 mg progesterone induced a luteal phase of normal duration in persistently estrous NC—males. The onset of anovulatory state, therefore, does not seem to be paralleled by changes in luteal control mechanisms. It is concluded that in contrast to the situation in neonatally androgenized rats the control of luteal activity in NC—males shows female characteristi...