Obstructive nephropathy induced with DL-potassium hydrogen tartrate in F344 rats

We experienced obstructive nephropathy in F344 rats treated with DL-potassium hydrogen tartrate (PHT) in a 13-week oral repeated dose toxicity study. Six-week-old male and female F344/DuCrj rats were fed a diet containing up to 2.0% PHT for 13 weeks. Microscopical findings including irregular dilation of the distal tubule lumen, foreign body giant cells, inflammatory cell infiltration, and regeneration of renal tubules were observed focally or multifocally in the renal cortex and/or medulla in the 0.5% and higher dosage groups of both sexes. The severity of these lesions increased in a dose-dependent manner. In the urinalysis, an increase in protein and white blood cells or the concentration of tartaric acid was detected in the 0.5% PHT and higher dosage groups of both sexes or males, respectively, though conventional blood biochemical analysis did not indicate failure of renal function. These results indicate that the PHT induces obstructive nephropathy in rats. There were no other treatment-related changes in other organs.