Sodium retention in response to saline infusion in uncomplicated diabetes mellitus

The response to a 21 infusion of physiological saline infusion was studied in 7 male uncomplicated insulin-dependent diabetics and in 7 non-diabetic male controls. The urinary sodium excretion in the diabetics in each of the 4 hr following the infusion was approximately half that of the controls. The total induced sodium excretion in controls was 34 +/- 4 mmols (mean +/- SEM) but only 14 +/- 4 mmols in the diabetics (p less than 0.005). The hourly creatinine clearance rate was higher in diabetics than in controls indicating a mechanism of reduced sodium excretion via enhanced tubular reabsorption rather than impaired filtration. This propensity to sodium retention in diabetics may play a role in the tendency to cardiovascular and renal complications.