Effect of carcinogenic nitroso compounds on rat kidney proximal tubule NAD levels.

An exposure of proximal tubules to alkylating nitrosamines is not necessary to deplete their NAD levels. Further work is needed to test if the poly(ADP-ribose) transferase induction theory accounts for the observed depletion of intracellular NAD. Also the viability of proximal tubule cells in the conditions of the study must be determined. Phosphate uptake by BBM vesicles prepared from chilled proximal tubules compared to those from proximal tubules incubated at 37 degrees C is a useful model for examining the role of intracellular NAD in renal Na+ gradient-dependent Pi transport. More experiments are required to assess the significance of changes in Pi-uptake by BBM vesicles induced by depletion of proximal tubule NAD content.