STUDIES ON THE MECHANISM OF THE HYPERCHOLESTEROLEMIA AND HYPERCALCEMIA INDUCED BY ESTROGEN IN IMMATURE CHICKS

Abstract

Injn. of estradiol dipropionate into immature , chicks resulted in large increases in serum Ca, cholesterol, inorganic P, lipid P and protein P. When thyroxin and estradiol dipropionate were injected simultaneously no increase in these blood constituents resulted. Simultaneous injn. of thyroxin had no inhibiting effect, however, on the growth of the oviduct in immature [female] chicks due to estrogens. Thiouracil produced a rise in serum cholesterol without affecting the other serum constituents mentioned. Changes in serum cholesterol due to adm. of estrogens or thiourea were not accompanied by changes in the total cholesterol content of the body. They were due to shifts in the distribution of cholesterol between plasma and tissues. From the data presented it seems probable that the estrogen-induced increase in serum Ca is due to the formation of the organic P compounds necessary to bind the Ca. Thyroxin prevents this rise by inhibiting the formation of, or causing the destruction of, these compounds.