A. N. Contopoulos

Increased erythropoietic stimulant in plasma of pregnant rats.

Summary 1. Plasma of normal adult female rats contains a factor capable of stimulating erythropoiesis in hypophysectomized and newborn rats, as judged by increased circulating red cell volume and hemoglobin. 2. This humoral erythropoietic factor is markedly increased during pregnancy. 3. Injections of plasma from non-pregnant and pregnant rats resulted in an increase in plasma and blood volumes of hypophysectomized and newborn recipients.

Pituitary and Plasma Bioassay for Trophic Hormones in the Alloxan-Diabetic Rat.

Summary The gonadotrophic, thyrotrophic, and growth hormone content of anterior pituitaries from female rats rendered diabetic by alloxan was determined by bioassay in hypophysectomized female rats. Trophic hormones in blood plasma were also determined. The number of glands required to evoke minimum follicle stimulating, interstitial cell stimulating, and thyrotrophic activity were the same in diabetic and normal rats, whereas growth hormone content of the pituitary was reduced 16-fold. The titer of circulating growth promoting factors was also reduced.

Increased metabolic rate without thyroid participation on injection of rats with pituitary erythropoietic fractions.

Summary 1. Erythropoietically active pituitary preparations increased the metabolic rate of hypophysectomized rats to normal levels with little or no stimulation of the thyroids. 2. A potent thyrotrophic preparation was less effective in increasing oxygen consumption than the erythropoietic factor. 3. The erythropoietic factor increased the caloric output to normal levels in rats in which all functional thyroid tissue had been destroyed.

Failure of Newborn Rat to Respond to Hypoxia with Increased Erythropoiesis.

Summary Suckling rats, between the age of 4 to 16 days, do not respond to hypoxia with an increased erythropoiesis as judged by increased hematocrit, hemoglobin and red cell volume.