Effects of Withdrawal of Growth Hormone and Cortisone Treatment on the Blood Picture of Hypophysectomized Rats

¹ From the Department of Biology, New York University, New York City

Peripheral red cell counts of hypophysectomized rats were largely unaffected by chronic treatment with either cortisone or growth (STH) hormone. However, upon withdrawal of treatment, red cell counts tended to rise in the STH-treated rats and to fall in those administered cortisone. The values at this time mirrored the alterations observed in the bone marrows of the treated rats. The postinjection shifts in peripheral red cell numbers were probably the result of oppositely occurring alterations in plasma volume. Leucocytic values induced by prolonged cortisone treatment tended to return to normal levels at approximately 2 weeks after stoppage of injections.