THE RELATION OF THE THYROID TO MAMMARY GLAND GROWTH IN THE RAT

Abstract

Studies were made on structural changes in the mammary glands of [female] rats which followed thyroid removal, with and without the influence of estrogen. Removal of the thyroid in normal [female][female] resulted in a thickening of the ducts, and an increase in the number of the lateral and end buds. A similar result was obtained in spayed [female][female]. Injs. of estrogen into spayed rats and spayed thyroidectomized rats brought about a greater thickening of the ducts and a greater increase in the number of lateral and end buds than in any of the other expts. Thyroxin tended to prevent these changes in the thyroidectomized rats. A discussion of possible mechanisms is presented.