Hyperinsulinemia in rats with alloxan diabetes after oral administration of insulin-containing negatively charged liposomes

Abstract

The effect of oral administration of insulin-containing negatively charged liposomes on the immunoreactive insulin level and glucose concentration in the blood of rats with alloxan diabetes was studied. Liposomes were formed from equimolar mixtures of either natural phosphatidylcholine and phosphatidylinositol or semisynthetic dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidylethanol. More than 70% of insulin was encapsulated in liposomes at initial molar lipid to insulin ratio 100:1. Oral administration of both liposomal species results in hyperinsulinemia. Hyperinsulinemia induced by liposomes from semisynthetic phospholipids is attended by a decrease of blood glucose concentration. No correlation between insulin level and glucose concentration in the rat blood after oral intake of phosphatidylinositol-containing liposomes is observed.