Erythropoietin in vitro. III. Perfusion of a lung-kidney preparation

Abstract

A critical review of six studies of perfused kidneys suggests that the methods used do not quite justify the common conclusion that an isolated kidney is capable of generating erythropoietin in response to hypoxia. In a repeat study, the gas tensions and pH were adjusted carefully in a perfused isolated dog lung-kidney preparation and the erythropoietin assays were carried out on standardized polycythemic rats or mice. In all of 13 technically successful experiments no generation of erythropoietic material could be demonstrated after 4 hr of perfusion with normal, hypoxic, or anemic blood. This unexpected result is discussed and it is suggested that erythropoietic material is released only from injured and disintegrating renal tissue but not from well-preserved and metabolically active kidneys.