[Demonstration of seasonal variations of circadian rhythm in gentamicin-induced chrono-nephrotoxicity in rats].

The present study investigates the chronobiological approach of the gentamicin-induced nephrotoxicity in rats treated with a single sublethal dose administered at different times of day and season of year. The nephrotoxicity is appreciated by gamma-glutamyl-transferase and alanine-amino-peptidase, two enzymes of the brush border cells and N-acetyl-beta-D-glucosaminidase, a lysosomal enzyme. These excretions peak out at 8 p.m. and reach a through at 8 a.m. for the experimentation in january-february. In contrast, for the experimentation in June-July, we evidence gamma-glutamyl-transferase and alanine aminopeptidase excretion increased at 2 p.m. and decreased at 8 p.m. So, we evidence with gentamicin not only a circadian but also a seasonal susceptibility in rats.