DIFFERENTIAL EFFECTS OF NEPHROTOXIC AGENTS ON RENAL ORGANIC ION TRANSPORT AND METABOLISM

¹ Drug Research Laboratories, Health Protection Branch, Tunney's Pasture, Ottawa, Canada

Administration of 25 mg/kg or 40 mg/kg of potassium dichromate or 40 mg/kg of potassium chromate resulted in a significant enhancement of N-methylnicotinamide uptake by renal cortical slices when measured 24 hours after a single subcutaneous injection. The kidney weight to body weight ratio, kidney water content and extracellular space also were increased. A significant increase in the uptake of p-aminohippurate by renal cortical slices was observed 24 hours after injection of 5 mg/kg of potassium dichromate. Addition of 10^-4 M potassium dichromate in vitro stimulated N-methylnicotinamide uptake by renal cortical slices, while p-aminohippurate uptake, gluconeogenesis and oxygen consumption were inhibited. Blood urea nitrogen levels were elevated 24 hours after administration of 25 mg/kg of potassium dichromate, while gluconeogenesis by kidney slices was inhibited and -aminoisobutyric acid transport was unchanged. Mercuric chloride (2.5 or 5 mg/kg) did not alter either p-aminohippurate or N-methylnicotinamide transport by renal cortical slices when measured 24 hours after injection and inhibited transport at 72 hours after injection. The results suggest that injection of potassium dichromate stimulates renal organic base transport by interacting with specific transport receptors in the pars convoluta, and that organic acid transport is also enhanced under certain conditions.