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Glomerular response mechanisms to glycemie changes in insulin–dependent diabetics

1987; Elsevier BV; Volume: 31; Issue: 4 Linguagem: Inglês

10.1038/ki.1987.100

1523-1755

Martin Wiseman, Ruggero Mangili, M. Alberetto, H. Keen, Giancarlo Viberti,

Dialysis and Renal Disease Management

Glomerular response mechanisms to glycemic changes in insulin-dependent diabetics.Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured by constant inulin and PAH infusion during euglycemia and intravenous dextrose-induced moderate hyperglycemia in seven insulin-dependent diabetics with persistently elevated GFR, seven diabetics with normal GFR, and in six normal control subjects.In euglycemia, RPF was higher and calculated renal vascular resistance (RVR) lower in the hyperfiltering than the normofiltering group (P < 0.05 for both variables), but filtration fraction (FF) was similar in all groups.During hyperglycemia, mean GFR rose significantly from 157 20 to 174 30 mllmin/1.73m2 (11.9%;P < 0.05) in the hyperfiltering group only.There was no statistically significant change in mean GFR in the normofiltering diabetic ( 1166 vs. 114 13 ml/min/l.73m2) and the normal control groups ( 11715 vs. 113 14 mllmin/l.73m2).RPF and FF rose by 5.8% and 9.2%, respectively, in the hyperfiltering group only, with no change in the normofiltering or normal control groups.No change in RVR was found in any group.Total tubular sodium reabsorption was higher during euglycemia in the hyperfiltering diabetics (P < 0.01), and rose significantly during hyperglycemia (P < 0.05) in this group only.Overnight euglycemia did not remove the increased glomerular filtration and flow of hyperfiltering diabetics.Hyperglycemia further accentuated hyperfiltration by elevating renal plasma flow and filtration fraction.There is evidence that glomerular hemodynamic perturbations with increased glomerular filtration rate (GFR) and raised intraglomerular pressure can markedly influence the natural history of the pathological lesions of diabetic and other glomerulopathies [1][2][3][4].A high GFR has been known to occur in a proportion of young onset diabetics for many years [5,6], and recent studies suggest that diabetic patients who have elevated GFR lose glomerular function at a faster rate than those with normal GFR, and progress to diabetic renal failure [7].The mechanisms behind this hyperfiltration, however, remain largely unexplained [8][9][10][11][12][13][14].