The corpus luteum-pituitary relationship: the lack of an inhibiting effect of progesterone on the secretion of pituitary luteotrophin.

Abstract

Neither hemiovariectomy nor the administration of 2.0 or 4.0 mg./day of progesterone for 8 days affected the size of the corpora lutea of pseudo-pregnant rats. The same lack of effect of hemiovariectomy, or of treatment with progesterone (5.0 or 10.0 mg./day for 28 days) on the size of the corpora lutea was seen in hypophysectomized rats bearing auto transplanted pituitaries. These results, in comparison with those of other target organ hormones on the secretion of their pituitary trophins, were interpreted as evidence that the progesterone- LTH relationship is not one of negative feedback.