Protein catabolism in cultures of hepatocytes derived from mice of various ages.

The degradation of pulse-labeled protein was measured in cultures of hepatocytes derived from mice of 3--4, 15--16, and 28 months of age. The rates of protein degradation were determined in culture media with varying amino acid, insulin, and glucagon concentrations. No differences with age were seen. Also no difference with age was detected in the lysosomal degradation of 125I-labeled asialofetuin.