ENDOTHELIN EXCRETION DURING KETOACIDOSIS DOES NOT CORRELATE WITH TUBULAR DYSFUNCTION

Urinary excretion of endothelin was measured by radioimmunoassay in ch ildren with diabetes mellitus during severe ketoacidosis and 12 days l ater when blood pH and blood glucose concentrations were normal. Metab olically stable diabetic children served as controls. Results from app arently healthy children without diabetes mellitus were used as normal values. Renal tubular injury was evaluated by the urinary excretion o f the proximal tubular marker alpha(1)-microglobulin and the distal tu bular marker Tamm-Horsfall protein (THP). During ketoacidosis we detec ted a decreased glomerular filtration rate associated with highly sign ificant changes in the excretion of eel-microglobulin, indicating prox imal tubular damage, and THP, suggesting disturbance of cells of the a scending loop of Henle. The daily excretion of endothelin was unaltere d but the ratio of endothelin/creatinine or endothelin excretion/creat inine clearance were significantly enhanced. In conclusion, we could d emonstrate that, despite a proximal and distal tubular cell dysfunctio n, endothelin excretion is not elevated during ketoacidosis. The incre ased endothelin excretion when related to creatinine clearance may be a consequence of disturbed proximal tubular function or dysfunction of the renal medulla.