RNA synthesis in rabbit and rat kidney under experimental changes in erythropoiesis.

RNA synthesis in rabbit and rat kidneys and erythropoietin level in plasma were studied under hypoxic stimuli (bleeding, phenylhydrazine and cobalt treatment, exposure to simulated altitude of 6000 m). An increase in renal RNA synthesis and in plasma erythropoietin activity was found. By using the "endocrine" kidney it was shown that 4-hr hypoxia produced a considerable increase in RNA synthesis both in the intact and in the "endocrine" kidney. The increase was correlated with the increase in the plasma titre of erythropoietin. The plasma titre of erythropoietin in rats having a single endocrine kidney also increased after 4-hr hypoxia. It is suggested that the renal biogenesis of erythropoietin under hypoxic stimuli involves, apparently, the mechanism of derepression of specific RNA synthesis.