A study of the effects of angiotensins 1, 2, 3 and bradykinin on the replication of bovine retinal capillary endothelial cells and pericytes.

The renin-angiotensin system of the human eye may play a role in the regulation of retinal blood flow and the development of new vessels. We have investigated whether angiotensins 1, 2 and 3 or bradykinin, in concentrations ranging between 1 x 10(-12) and 1 x 10(-6), have any mitogenic activity on cultured bovine retinal endothelial cells (BREC) and pericytes (BRP). Cell replication was assessed by 3H-thymidine incorporation and, in the case of BREC and AT-2, also by cell counts. AT-2 was also tested on bovine aortic EC (BAEC). None of the substances elicited any response on BREC, BRP or BAEC. Whether angiotensin(s) induce angiogenesis in retinal vessels in vivo remains to be established but this does not appear to occur through direct stimulation of cell replication.