EXPRESSION OF AN ERYTHROPOIETIN-LIKE GENE IN THE TROUT

Cross-species Northern blot hybridization and radioimmunoassay have pr ovided evidence for the expression of an erythropoietin (EPO)-like gen e in the rainbow trout. The principal site of EPO-like mRNA and antige n expression in the adult trout appears to be the kidney which also ac ts as the major erythropoietic organ. The data suggest that a locally produced EPO-like factor may regulate renal erythropoiesis in bony fis h and, furthermore, they identify a possible evolutionary origin for r enal EPO production in mammals.