Effects of Different Anterior Pituitaries and Human Pregnancy Urine on Rat Sex Organs. ∗

We have shown^{1, 2} that anterior pituitaries of different species as well as urine of pregnant women act differently on the sex organs of the guinea pig. The anterior pituitary of rat, rabbit, cat and guinea pig caused enlargement and maturation of follicles, formation of pseudo-corpora lutea and interstitial gland, and in some cases induced an ovulation. Injection of extracts as well as inoculation of pieces of anterior pituitary of cattle, hog and sheep produced an atresia of follicles so intense that it could not be attributed merely to a loss in weight of the animals; furthermore it gave rise to the formation of rudimentary interstitial gland and of usually small pseudocorpora lutea, which were essentially derived from hypertro-phying theca interna and connective tissue elements, although in some cases a limited participation of granulosa could not be excluded. In exceptional cases we observed apparently an ovulation at very early stages following administration of this kind of anterior pituitary. Urine of pregnant women resembled in its action the anterior pituitaries of rabbit and rat, but differed from them in that it did not produce large mature follicles in the ovaries of the injected animals.

Since, as a test animal for the presence of anterior pituitary-like substances, the rat is commonly used, we now have studied the action of anterior pituitary of different species and of the urine of pregnant women on rats, to determine how far the results obtained were similar to those obtained in the guinea pig. For the most part young rats, weighing between 30 and 40 gm., but in some cases older animals, with initial weights of approximately 50 and 75 gm., were used. As in our former investigations, we studied microscopically in each case the ovaries in serial sections and parts of the other organs.