RECEPTOR-MEDIATED INTERNALIZATION OF ANGIOTENSIN-II IN BOVINE ADRENAL-MEDULLARY CHROMAFFIN CELLS IN PRIMARY CULTURE

Binding and internalization of angiotensin II (AII) were studied on bo vine adrenal medullary cells in primary culture. Binding of [I-125]AII was reversible, saturable, specific and showed high affinity. AII was found to be internalized by bovine adrenal medullary eels. Monensin i ncreased whereas phenylarsine oxide (PhAsO) decreased the internalizat ion. Excess of unlabelled AII or saralasin could block the internaliza tion, indicating a receptor mediated internalization process. The kine tic analysis indicated that, during the first 4 min, about 25% of the membrane bound ligand was internalized per min and the recycling of in ternalized ligand and receptor initiated around 4 min.