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Glomerular filtration rate (GFR) was measured by constant infusion of iothalamate in conscious rats with and without streptozotocin diabetes. Kidney weight had already increased significantly after 4 days of diabetes. GFR was unchanged at that time, but increased subsequently, so that GFR/kidney weight was normal after 1 month of diabetes. Tubular glucose reabsorption rate was increased to the same extent as kidney weight after 4 days of diabetes. It is concluded that renal growth in experimental diabetes cannot be initiated by glomerular hyperfiltration, but that increased glucose reabsorption may have a causal role.

The kidney changes seen in rats shortly after the induction of experimental diabetes were reviewed: Kidney weight increases by 15 to 20% during the first 4 to 5 days of diabetes and by 70 to 90% after some weeks. GFR increases after a lag-time of some days in parallel to kidney weight. Morphometric analysis shows glomerular hypertrophy to be prominent during the first few days of diabetes. The glomerular filtration surface increases by 40% after 4 days. Diabetic renal hypertrophy is related to the severity of the diabetes, and kidney growth rate relates linearly to blood glucose. Moderate diabetes mellitus and unilateral nephrectomy have approximately the same effect on the kidney (weight increase 20%/4 days). When diabetes mellitus and nephrectomy are combined, renal growth rate almost doubles.

Juvenile diabetic patients were studied 60-72 hours after insulin withdrawal when moderate ketoacidosis had developed. Somatostatin infusion for 4 hours in five patients resulted in almost complete suppression of plasma pancreatic glucagon and growth hormone, a fall in plasma-cyclic-adenosine-monophosphate (A.M.P.) concentrations, and a large fall in plasma-glucose concentration. After infusion plasma concentrations of these substances rose again. Blood-ketone-bodies, plasma-free-fatty-acids (F.F.A.), and plasma glycerol concentrations, however, did not decrease appreciably with somatostatin administration. In three patients 2 to 3 h somatostatin infusions were twice superimposed upon a continuous 9-5 h insulin infusion (1 unit/h). An insulin effect was noticeable within 30 minutes, with pronounced falls in the concentrations of plasma glucose, pancreatic glucagon, F.F.A., and blood-ketone-bodies. There was no significant change in these patterns when somatostatin was administered or withdrawn. These results do not indicate that somatostatin infusion would be useful in the treatment of manifest diabetic ketoacidosis.