EFFECTS OF HORMONES ON ERYTHROPOIESIS IN THE HYPOPHYSECTOMIZED RAT

Abstract

In the hypophysectomized rat thyroxine caused blood picture changes resembling those produced by testosterone: markedly increased erythrocyte number, slightly increased hemoglobin, reticulocytosis, and bone marrow repair. Prolactin produced similar but less pronounced alterations. DCA maintained the red cell count and Hb level above those of untreated controls, but without producing marrow repair. The thyroids of animals treated with testosterone, prolactin and DCA were like those of untreated hypophysectomized rats, in weight and histological appearance. There was no increase in O2 consumption in hypophysectomized rats treated with DCA, cortical hormone or testosterone. Some hormones can act as erythropoietic agents without altering the rate of O2 consumption, and these effects, in the hypophysectomized rat, are not mediated through the thyroid gland.