EXHAUSTION PHENOMENON IN THYROID PRODUCED BY PITUITARY TREATMENT: HISTOLOGICAL STUDY OF RABBIT’S THYROID UNDER VARYING DEGREES OF ANTERIOR PITUITARY THERAPY

Abstract

In the course of a series of experiments on the relationship of the anterior pituitary body to the thyroid gland, we observed that the degree of hyperplasia obtained by prolonged treatment of rabbits with crude extracts of anterior lobe tissue did not parallel the dosage or the duration of treatment. We were struck by the appearance of the thyroid glands of animals which had received rather large doses of pituitary materials over a period of more than seven days. They showed involutional and atrophic changes which were totally unexpected since it was assumed on a priori grounds that they would show increments of hyperplasia with the increased dosages and duration of the injection periods. Fifty rabbits of the blue bevern and Flemish giant strains were used. They ranged from 14 to 20 weeks of age. It was early evident that strain, alone, had no great influence upon the normal histology of the rabbit’s thyroid. The first experiments in the series were made using saline emulsions of freshly obtained anterior...