Abstract
Hohlweg and Dohrn 1 recently reported the induction of precocious sexual maturity in immature castrate female rats through the implantation of infantile ovarian tissue 3 weeks after oophorectomy. In connection with some experimental work on the anterior pituitary the writer had occasion to confirm and extend their observations.
Ten to 14 day old females, each with litter mate controls both normal and castrate, were gonadectomized and allowed to run for approximately 21 days. Two immature ovaries were then implanted intramuscularly in the experimental animals, the donor age varying from 9 to 35 days. At the time of vaginal opening the animals were sacrificed and grafts and pituitaries were prepared for histological study. The results are summarized in Table I.
It will be seen that in every instance in which the ovarian grafts proved successful the experimental animal matured considerably earlier than its litter mate controls, as evidenced by vaginal canalization and by an oestrous smear. When the experimental animal failed to mature precociously, histological examination of the grafts revealed absence of ovarian tissue. Moreover, in unsuccessful cases, the experimental animal and the castrate controls matured at about the same time—considerably later than the unoperated control. Results show also that the experimental animals usually matured within 7-10 days, despite the fact that the age of ovaries employed for transplants varied from 9 to 35 days. In 2 instances (Litters 4 and 7) the normal animals matured too early to render results of any significance.
It appears probable from these data that the castration pituitary stores sex hormone which is liberated under the influence of the transplanted ovaries, causing the latter to mature precociously.
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