EFFECT OF PROLACTIN ON ERYTHROPOIESIS IN THE MOUSE.

The effect of prolactin, growth hormone, progesterone, testosterone, lactating mouse plasma (fifth postpartum day), pregnant mouse plasma (sixteenth to nineteenth day of pregnancy) on erythropoiesis in the polycythemic mouse has been studied and compared. Prolactin was found to stimulate erythropoiesis in the intact mouse. Also, pregnant mouse plasma and lactating mouse plasma had an erythropoietic stimulating effect. Prolactin produced an increase in the red cell mass when administered over a prolonged period to normal and orchidectomized mice. This suggests that the testes are not necessary for the action of prolactin. It is suggested that prolactin could function as an erythropoietic stimulatory component in pregnant and lactating mouse plasma.