The effect of lysosomal inhibitors on protein degradation in cat hepatocyte monolayers

1. Isolated cat liver cells were established in monolayer culture and intracellular proteins were labelled for 20 hr with L-[4,5-3H]leucine. 2. The known intralysosomal protein degradation inhibitors such as NH4Cl, leupeptin, cycloheximide and insulin were all effective in decreasing the rate of proteolysis in cat hepatocytes. However, the maximum inhibitory effects of these agents were generally lower when compared to the rat. 3. These results indicated a smaller contribution of the lysosomal pathway towards overall protein degradation in cat liver.