LOCALIZATION OF ERYTHROPOIETIN GENE-EXPRESSION IN PROXIMAL RENAL TUBULAR CELLS DETECTED BY DIGOXIGENIN-LABELED OLIGONUCLEOTIDE PROBES

Erythropoietin (EPO) is the main humoral stimulus of erythropoiesis. I n adult mammals, the kidney releases EPO in response to hypoxic stress . Conflicting data have suggested either renal tubular or peritubular cell origins of EPO synthesis in vivo. In situ hybridization studies w ere performed to define further the kidney cell type(s) capable of inc reasing EPO gene expression during hypoxic stimulation. EPO gene expre ssion was stimulated in mice exposed to acute hypobaric hypoxia. Kidne ys from hypoxic and control normoxic mice mere obtained. Six digoxigen in-labelled oligonucleotide probes complementary to EPO exon sequences were utilized for in situ hybridization for EPO messenger RNA, Positi ve hybridization signals mere identified in some proximal tubular cell s, confined to the inner third of the renal cortex of hypoxic mouse ki dney.