Erythropoietin production in the fetal lamb.

Abstract

Abstract Five fetal lambs (day 95 to 123 of gestation) received chronic injections of phenylhydrazine by direct introduction into their jugular veins. Erythropoietin (ESF) appeared in the plasma of these fetuses, and the quantities of ESF present were directly related to the intensity of anemia induced by the phenylhydrazine. No ESF was demonstrable at any time in the maternal plasma. Fluctuations in the levels of ESF in fetal plasma, which were characteristic of the response, may be due to variations in the quantities of plasma substrate upon which the renal erythropoietic factor (REF) operates to produce the ESF. The results of this study establish with certainty the ability of a mammalian fetus to produce the ESF in response to a form of hypoxia.