A comparison of the effects of oral and intravenous glucose administration on renal calcium excretion in the rat.

Standard renal clearance techniques were used to compare the effects of oral and intravenous glucose administration on renal calcium handling in the rat. A significant (P less than 0.01) calciuric response was evident in both groups following glucose loading. The maximal effect in the oral group, however, was slightly delayed. The increased urinary calcium excretion in both groups was the result of a reduction in fractional calcium reabsorption. The filtered load of calcium was unchanged. The response was also independent of changes in urinary sodium output, urine flow rate and glycosuria. The role of insulin in the response remains unclear.