The functions of the corpus luteum.—IV. The relation of œstrin to the luteal phase of the œstrous cycle

Abstract

The prolonged administration of large amounts of oestrin (up to 25,000 mouse units in 3 weeks) to immature, ovariectomized or anoes-trous rabbits and ferrets leads to the typical oestrous condition of the uterus, but none of the changes typical of pseudo-pregnancy, i.e., of the luteal phase, appear. In the mammary glands an accentuation of the oestrous growth of the ducts leads to a superficial resemblance to the condition found in early pseudo-pregnancy, but the extensive growth of alveoli characteristic of the luteal phase does not occur. In the ferret, cornification of the vaginal epithelium, in addition to the vulval swelling, is found during oestrus,'' but both disappear during the luteal phase. Prolonged oestrin injection causes the prolonged appearance of both of these symptoms of oestrus. The pseudo-pregnant changes in the accessory organs are, therefore, not produced by even the prolonged action of oestrin alone, and this hormone is not, therefore, the causative factor in the changes of the luteal phase. On the other hand, oestrin is not antagonistic to the uterine and mammary changes of oestrus; in fact, as shown by various workers (Allen, 1930; Weichert, 1928), it prepares the uterus for the action of the hormone of the corpus luteum.