Alteration of the Proteins of the Pituitary Gland of the Rat by Estradiol and Cortisol

Abstract

The major electrophoretic component seen in extracts of pituitary glands of rats disappears when the animals are made hypothyroid. The disappearance could be prevented by administration of estradiol or cortisol. Bio-assay of the major band and whole extracts of glands from hypothyroid rats treated with cortisol showed a normal amount of growth hormone, indicating that when the major band remained growth hormone activity was maintained. With glands of untreated hypothyroid rats, only a small amount of growth hormone was present in the area of the column normally occupied by the major component. Whole glands from hypothyroid animals were also essentially devoid of growth hormone. Growth hormone that had been isolated from pituitary glands of normal rats by fractionation with ethanol had the same electrophoretic mobility as the major electrophoretic component seen in hypophysial extracts from normal rats. (Endocrinology76: 362, 1965)