Early diabetic kidney maintains the corticomedullary urea and sodium gradient.

Early diabetic nephropathy is largely undetectable before substantial functional changes have occurred. In the present study, we investigated the distribution of electrolytes and urea in the early diabetic kidney in order to explore whether pathophysiological and metabolic changes appear concomitantly with a decreased sodium and urea gradient. By using hyperpolarized (13)C urea it was possible to measure the essential intrarenal electrolyte gradients and the acute changes following furosemide treatment. No differences in either intrarenal urea or sodium gradients were observed in early diabetes compared to healthy controls. These results indicate that the early metabolic and hypertrophic changes occurring in the diabetic kidney prelude the later functional alterations in diabetic kidney function, thus driving the increased metabolic demand commonly occurring in the diabetic kidney.