Reduced degradation of biological active peptides during in vitro aging of endothelial cells.

Endothelial cells under in vitro cultivation show an age-dependent decrease in peptide-cleavage activity. After a number of passages, the rates of Leu-enkephalin and bradykinin decomposition by cultivated cells were diminished as compared to their counterparts before in vitro aging. In addition, these cells have been found to be less capable of converting angiotensin I into angiotensin II. Such phenomena could be interpreted as correlated with age-related disturbances concerning the regulation of vascular functions in vitro.