Abstract
Loeb, Bassett, and Hilda Friedman 1 , 2 , 3 have shown that intraperitoneal injections of acid or alkali extracts of the anterior pituitary of cattle cause in the guinea pig a remarkable hypertrophy and hyperplasia of the thyroid gland associated with liquefaction and absorption of colloid. Martin Silberberg 4 has studied the combined effect of KI and this extract on the thyroid gland and W. J. Siebert 5 has determined the effect of various preparations of the anterior pituitary gland on the basal metabolism under various conditions. In our former investigations we used as a criterion of hypertrophy the microscopic changes in the thyroid gland after anterior pituitary injections. The thyroid glands of the injected animals appeared distinctly larger than the normal thyroids.
We sought to determine the changes in weight of the thyroid glands produced by these preparations, in order to obtain quantitative data as to the intensity of the hypertrophy and hyperplasia. We carried out 3 experiments, the results of which are shown in the following table.
In the first 2 experiments, the average initial weight of the injected as well as of the control guinea pigs was approximately 191 gm. During the period of treatment (5 days for the first experiment and 6 days for the second), the average weights of the injected animals remained almost unchanged, while the controls gained on the average of 10 and 8 gm. respectively. As a result of the injections the thyroid approximately doubled its weight. In the third experiment in which we had to deal with somewhat heavier guinea pigs, weighing on the average 265 and 264 gm. respectively, the average weight of the thyroid of the injected animal is seen to be approximately 2 1/2 times greater than the weight of the gland of the control guinea pig.
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