Inhibition of Menstruation by Crystalline Progesterone

Abstract

It has been shown 1 that partially purified extracts of the corpus luteum, containing progesterone, possess the property of inhibiting menstruation in the monkey. In view of the possibility that contaminating substances were involved in this result, the experiments have been repeated on five animals with crystalline progesterone, both natural and synthetic.

The hormones used consisted of 2 lots of β-progesterone prepared in our laboratory from sows ovaries, 2 lots of synthetic β-progesterone donated by the Schering Corporation through the kindness of Dr. Erwin Schwenk, and a lot of synthetic α-progesterone donated by E. Merck, Darmstadt. The animals were chosen and the experiments conducted in the same way as those of Corner, 1935. 1 Each animal was allowed one or more control cycles and the time of the next menses having been estimated as closely as possible from the history, treatment with progesterone was begun about a week before the expected onset. The dosage was uniformly 1 mg. daily, equivalent to 1 international unit. One animal received natural β-progesterone throughout. Two received the first of the Schering preparations for 11 days, and then the second Schering preparation for 5 and 6 days respectively; menstruation then being overdue, the experiments were continued with natural progesterone for a few days longer. Finally, 2 received the Merck α-progesterone throughout. In all 5 experiments, the expected menstruation was delayed for about 2 weeks, after which the hormone was discontinued according to plan. Bleeding began 2 to 4 days thereafter.

The only feature in which the result with crystalline progesterone differed from that with the partially purified substance used in previous experiments, was in the more rapid onset of bleeding after discontinuance, namely 2 to 4 days instead of 5 to 8. This may have been due to more rapid utilization or excretion of the pure hormone.

In conclusion, it may be stated that all 4 of the definitely established effects of corpus luteum extracts upon the uterus, namely progestational proliferation of the endometrium, 2 inhibition of action of pituitrin upon the myometrium, 3 inhibition of uterine motility in vivo, 4 and suppression of menstruation, 1 have now been achieved with crystalline progesterone.