Effect of Anterior Pituitary-like Hormone on the Ovary of the Hypophysectomized Mouse

Abstract

We have stated previously that preparations of A.P.L. (anterior-pituitary-like hormone) from pregnancy urine or placenta do not lead to maturation of follicles or formation of corpora lutea in the ovary of the hypophysectomized rat, 1 , 2 but only to luteinization of theca cells. Smith, 3 however, who repeated this experiment with the commercial preparation of the anterior pituitary-like hormone prepared from pregnancy urine bearing the name Antuitrin S., found that after such treatment new corpora lutea could be seen in the ovaries of both pre- and post-pubertal hypophysectomized rats; these were of the same type as the normal corpora lutea of the postpuberal animal. Thinking that the difference in results might be due to a difference in the preparations used, we repeated our experiment on 10 prepubertal (22-day-old) rats, using Antuitrin S.,∗ but the results were the same as in our previous experiments. The ovaries of these rats showed no corpora lutea, and the only effect of the treatment was thecal luteinization.

It occurred to us that the difference in the results obtained by Smith and by us might be due to differences in the 2 colonies of rats. We decided, therefore, to repeat our experiments on a different animal species. The mouse seemed to be especially suited to an experiment of this type, because the corpora lutea existing at the time of hypophysectomy disappear very rapidly after operation in the non-pregnant animal, and any normal corpora lutea seen in the ovary a few weeks after hypophysectomy would have to be ascribed to the treatment.

Fourteen adult female mice were hypophysectomized for this experiment, and after a period of 2 weeks A.P.L treatment was initiated in 10 of them; 4 were left as untreated controls. We gave 5 units daily for 9 days, and killed all the animals, including the controls, on the 10th day. We have not seen normal corpora lutea in any of these animals, and the only difference between the treated and the untreated animals was that the theca showed signs of luteal transformation in the former group, while in the latter this was not the case.

These experiments show that in the postpubertal mouse treatment with A.P.L. does not lead to the formation of corpora lutea, but only to luteinization of the theca cells.