| Abstract: | Disturbances of potassium, calcium, phosphate and magnesium homeostasis in diabetes mellitus are well documented. We have compared the effects of semisynthetic human and pancreatic porcine insulin on transmembrane shifts of these ions, and on glucose metabolism, at two insulin infusion rates, 20 and 50 mU/kg/h, during euglycaemic clamping for 2 h in 6 normal volunteers. The glucose requirements and the changes in blood metabolite concentrations were not significantly different during the porcine and human insulin infusions. Serum potassium levels, however, showed a significant greater decline with infusions of porcine insulin (4.2 +/- 0.1 to 3.5 +/- 0.1 mmol/l) compared with human insulin (4.2 +/- 0.1 to 3.7 +/- 0.1 mmol/l) at 50 mU/kg/h (P less than 0.05). Potassium levels were significantly lower during the porcine insulin infusion at 105 and 120 min and at 15 and 30 min after stopping the infusion. Electrocardiographic T-wave voltage decreased during the porcine and human insulin infusion by 0.13 +/- 0.02 and 0.10 +/- 0.01 mV, respectively (P less than 0.02). Changes in serum levels of magnesium, calcium, phosphate, and red blood cell concentrations of magnesium and 2,3-DPG, were not significantly different between the insulins. Thus a small but significant greater decline in potassium levels with similar glucose requirements was found during iv administration of porcine insulin compared with human insulin. |
