Effect of rHu-EPO on the phosphorylation of JAK-2 in rat livers and hepatocytes. Rat livers were perfused with 8.9 U rHU-EPO/ml and cultured hepatocytes incubated with 10 U/ml (both for 15 minutes). Afterwards, cytoplasmic and nuclear extracts were subjected to Western blotting. As a positive control for EPOR signalling whole cell extracts of the rHu-EPO-responsive cell line UT-7 were used that were treated with (or depleted from) rHU-EPO (10 U/ml for 15 minutes). Total JAK-2 and pJAK-2 were determined for extracts from (A) of perfused liver or (B) total cellular extracts from cultured hepatocytes. The blots represent results of 6 experiments with different animals.