Impairment of the Birth Mechanism Due to Hormones from the Anterior Hypophysis. ∗

Abstract

It has been shown in this laboratory 1 that the administration of the hypophyseal growth hormone (alkaline extracts of bovine hypophysis) during the last week of pregnancy in some way injures the birth mechanism. Treatment is stopped on day 21. There is then a characteristic prolongation of pregnancy of from 2 to 3 days, with final birth of dead or living foetuses. There are also instances of complete failure even to give birth to dead foetuses and of the consequent resorption of the latter. The effect has been shown to be due in all probability to changes which the treatment provokes in the ovaries of the pregnant animal, more especially to the formation of fresh lutein tissue there. 2

Now another hormone of the anterior hypophysis, one of the outstanding characteristics of which is the production of precocious maturity in young female rodents, strangely enough, in addition to its marked stimulation of the follicular apparatus also causes the luteinization of follicle walls, a point strongly emphasized by Zondek and Aschheim. 3 It might be expected, therefore, that whatever effects from growth hormone treatment are due to the creation of fresh lutein tissue in the ovary would also be encountered in the treatment of animals with this second hormone from the anterior hypophysis.

We propose to show that this is the case as regards interference with the mechanism of birth. Engle 4 has recently doubted the existence of these effects. His method consisted in daily implantation into the pregnant animal of anterior hypophyseal tissue—the most effective method, it must be admitted, of provoking the precocious maturity of young female rats and mice. The characteristic prolongation of gestation can be secured by anterior hypophyseal implants, for instance, by 1 or 2 glands daily for the last 5 days of gestation.