THE INDUCTION OF OVULATING HORMONE RELEASE FROM THE PITUITARY OF THE DOMESTIC HEN BY MEANS OF PROGESTERONE

Abstract

introduction

The induction of ovulation in the hen by means of progesterone was first noted by Fraps arid Dury (1943). Later, unpublished experiments of Fraps and his coworkers indicated that the probable cite of action of this hormone was the bird’s own pituitary. These experiments showed (1) that the ovarian follicles of hens that had been treated with pregnant mare’s serum could not be ovulated with progesterone, but were capable of being ovulated with luteinizing pituitary substances; and (2) that the pituitaries of these hens treated with pregnant mare’s serum were considerably lower in ovulating potency than the pituitaries of normal laying hens.

The present studies were undertaken to determine as conclusively as possible whether or not progesterone induced a release³ of ovulating hormone from the pituitary of the treated hen, and to what extent this release resembled the natural one. Because of the well known ovulation-inhibiting effect of progesterone in mammals, the question of progesterone inhibition of ovulation in chickens was also considered briefly.