Erythropoietin secretion by isolated rat Kupffer cells.

Hepatic parenchymal and Kupffer cells were isolated from regenerating rat liver and maintained in primary culture in an attempt to identify the cell type responsible for extrarenal erythropoietin (Ep) production. Conditioned media from Kupffer cell cultures were shown to contain Ep. Kupffer cells were cultured in the presence and absence of serum, but only cultures with serum contained bioactive Ep. The addition of latex beads to Kupffer cell cultures increased the amount of Ep secreted. Parenchymal-cell-conditioned media were negative for Ep activity. Isolated liver macrophages might be useful in vitro for the study of Ep elaboration.