In vitro degradation of endocytosed protein in pronephros cells of the char (Salmo alpinus L.). The effects of temperature and inhibitors.

In vitro degradation of 125I-formaldehyde treated human serum albumin (fHSA) in char (Salmo alpinus L.) pronephros cells was studied. The labelled protein was injected intravenously and after various intervals of time pronephros cells were isolated and degradation of internalized protein was measured. No degradation could be observed in cells isolated 30 min after injection. The degradation was very effective in cells isolated at later time points (60-90 min); as much as 65% of the initial cell associated labelled protein was degraded during 90 min incubation at 15 degrees C. The effect of temperature on degradation showed a linear course in the temperature range 0-20 degrees C when plotted in an Arrhenius plot. Monensin and ammonium ions inhibited degradation while colchicine had no effect when pronephros cells were isolated 75 min after the injection.