Effects of insulin on renal electrolyte handling

It has been recognized that insulin, beside its functions on extrarenal metabolic processes, also modulates the renal handling of different electrolytes. The effects of one intravenously administered bolus (0.1 U/kg BW) of insulin on renal electrolyte handling were investigated in children. Insulin without affecting the filtration rate of creatinine and the urine flow rate resulted in significant increases in urinary calcium (3.56 +/- 0.80 vs. 7.48 +/- 0.80 mumol/min/1.73 m2) and magnesium (2.44 +/- 0.41 vs. 4.29 +/- 0.5 mumol/min/1.73 m2) and a fall in potassium excretion (53.25 +/- 13.17 vs. 23.71 +/- 4.21 mumol/min/1.73 m2). Phosphate excretion showed an initial fall followed by a more than twofold increase afterwards (6.52 +/- 0.92 vs. 3.14 +/- 0.92 and 15.29 +/- 3.82 mumol/min/1.73 m2, respectively). On the other hand, urinary sodium excretion was unaffected (171.21 +/- 27.22 vs. 166.23 +/- 22.86 mumol/min/1.73 m2). Our data show that insulin may modulate electrolyte homeostasis by inducing changes in their renal tubular handling.