Hastening Development of Female Genital System by Daily Homoplastic Pituitary Transplants.

Abstract

The success of the writer 1 , 2 in restoring the atrophied sex apparatus of the hypophysectomized rat by daily homoplastic pituitary transplants, made it seem not unlikely that the transplants might hasten the development of the sex apparatus of the immature unoperated animal. A series of experiments was therefore undertaken in which homoplastic pituitary transplants, taken from full-grown rats of both sexes, were made daily in females which would not normally mature for some time.

It was found that this treatment rapidly induced the changes characteristic of sexual maturity, (opening of the vagina, uterine hyperemia and distension, follicle and corpora formation). These changes were secured as early as the weaning date (22nd day of life), the animals weighing approximately 40 grams. The vaginal smear was oestral in type. Structurally the changes indicative of sexual maturity were present in all parts of the genital system.

When the transplants were commenced at about the weaning date, sexual maturity was induced in 5 or 6 days. If the transplants were begun in animals considerably younger, a longer treatment was required. This was shown by one series (3 treated and 3 controls), in which treatment was instituted on the 14th day of life. One of the treted animals matured sexually in 8 days, two in 10 days. In no case have these transplants failed to bring about sexual maturity at a considerably earlier period than it would normally have occurred. The results obtained transcend all normal variability.

Experiments show that the anterior pituitary component of the transplant is responsible for the induction of the premature sexual maturity.

Kymographic records of the spontaneous contractions of the isolated uterus in Ringer's solution show that the amplitude of these uterine contractions in the treated animals greatly exceeds those of the controls; they, in fact, are equal or nearly equal to those of an animal which matures at the usual age.