Effect of Renal Disease on Renal Uptake and Excretion of Insulin in Man

Renal handling of insulin was studied over plasma insulin levels of 6 to 40 μU per milliliter in 13 patients by renal-vein catheterization. The kidney in normal subjects and 7 patients with moderate renal insufficiency — glomerular filtration rate (GFR) over 22.5 ml per minute per kidney per 1.73 M2 — removed 39 ± 4 per cent (SD) of the insulin from arterial plasma. Severe renal insufficiency (GFR less than 6) reduced insulin uptake to 9 per cent in four subjects, two with diabetic glomerulosclerosis. Mean GFR in normal subjects was 61 ± 11 (SD) and renal insulin extraction —renal plasma flow (RPF) × % uptake — was 106 ± 28 (SD). These findings suggest that a decreased uptake of insulin by damaged kidneys accounts in part for the diminished insulin requirements seen in patients with diabetic glomerulosclerosis and that all the renal uptake of insulin cannot be explained by glomerular filtration alone.