Erythropoietin production in cultures of goat renal glomeruli

Cultures initiated with isolated goat-kidney glomeruli produce erythropoietin over periods of 7 months. Production seems dependent upon a minimum interval of about 30 days between changes of medium. Experiments distinguishing between erythropoietin, renal activator, and serum substrate support the conclusion that the factor released to the medium of long-term glomerular cultures is erythropoietin itself. The system offers promising opportunities for studying regulation of erythropoietin production, and possibly could be developed as a source of significant quantities of the hormone.