Abstract
Smith and Engle 1 first showed that daily transplants of the anterior lobe of the pituitary induced precocious sexual maturity in immature female rats and mice and caused superovulation in these animals as well as those sexually mature. However, Riddle and Flemion 2 were not able to induce ovulation in immature pigeons using transplants of this gland. The present investigation was undertaken to determine the effect of daily transplants of the anterior lobe of the pituitary in frogs (Rana pipiens, Shreber).
In making the transplant the head of the donor was cut from the body with sharp scissors, the brain exposed, and the anterior lobe was quickly removed from the floor of the cranium and inserted into the lateral or femoral lymph sinus of the recipient. Throughout the experiment the animals were not subjected to temperature changes and were neither fed before nor during the experiment.
In November, 9 out of 11 females receiving transplants either ovulated without amplexus or the uteri were gorged with eggs when the animals were killed. One of the 2 frogs which did not ovulate was killed the fourth day after having received one transplant on 3 successive days. The ovary had apparently been stimulated because the oviducts were highly vascularized. When the second frog died on the eighth day, having received transplants for 4 days, no visible change had occurred in the oviducts.
From the experimental work it has been found that the number of transplants necessary to bring about ovulation varies in individuals. One transplant for 3 or 4 successive days will induce ovulation in most cases, however, 2 animals out of 13 receiving only one transplant ovulated. In no instance has ovulation occurred in the untreated frogs or in the controls which received grafts of brain tissue similar in size to the anterior lobe.
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