Erythropoietin production by interstitial cells of hypoxic monkey kidneys

Previous studies which demonstrated that interstitial cells of the peritubular capillary bed of the kidneys are the site of erythropoietin (Epo) production have been performed in non-primate species. In this study, kidneys from adult rhesus monkeys exposed to 18 h hypoxia (0.42 atm) with high serum (5685 mU/ml) and kidney (814 mU/g, includes serum EPO in the kidney) levels of Epo were compared with a kidney from a nonhypoxic normal rhesus monkey. Localization of Epo mRNA by in situ hybridization was carried out with either anti-sense or sense RNA probes generated from a 645 base pair KpnI-BglII fragment of a monkey Epo cDNA. Epo mRNA was demonstrated only in interstitial cells in the peritubular capillary bed of the hypoxic and normal monkey kidneys utilizing the antisense probe. The finding that the same type of cell that produces EPO in mice, rats and sheep also produces EPO in a higher primate species strongly supports the contention that renal interstitial cells also produce EPO in the human.