Biochemical and functional characteristics of cultured renal epithelial cells from uninephrectomized rats: factors influencing nephrotoxicity.

Primary cultures of renal proximal (PT) and distal tubular (DT) cells from control and uninephrectomized (NPX) Sprague-Dawley rats were established to characterize factors that are responsible for the altered susceptibility to nephrotoxicants that occurs after compensatory renal cellular hypertrophy. Cells were grown in serum-free, hormonally defined medium and parameters were measured on days 1, 3, and 5 of primary culture. PT and DT cells from control and NPX rats appeared to maintain epithelial characteristics in culture, as shown by cytokeratin staining, morphology, protein and DNA content, and enzyme activities. Activities of several glutathione-dependent enzymes, including gamma-glutamyltransferase, glutathione S-transferase, glutathione peroxidase, and gamma-glutamylcysteine synthetase, were significantly greater in PT cells from NPX rats than in PT cells from control rats when factored by protein content. Rates of alpha-methylglucose uptake across the basolateral and brush-border membranes and sodium-dependent uptake of glutathione across the basolateral membrane were 2- to 3-fold higher in PT cells from NPX rats than in PT cells from control rats. These results are consistent with the hypertrophied phenotype being maintained in primary cultures of PT cells from NPX rats. The marked alterations in transport may play central roles in the delivery of nephrotoxicants to the target cell, and thus, increases the probability of chemically induced injury or death. These findings also suggest that these cell cultures may be useful for the study of biochemical processes associated with compensatory renal cellular hypertrophy.