Effect of Oral Insulin on the Development of Small Intestine Carbohydrate Hydrolysis and Absorption in Suckling Rats

The study is conducted to reveal the effect of oral insulin on the development of carbohydrate hydrolysis and transport in the small intestine in suckling rats. Oral insulin administration (5 U/kg/day) from the 1 st to the 21 st day of postnatal life resulted in induction of the carbohydrate assimilation in the small intestine of growing rats. Oral insulin increased intestinal maltase, sucrase and lactase activity as well as absorption of free and hydrolysis-dependent glucose from maltose in the small intestine of suckling rats. The effect was age-dependent and was clearly expressed during the second half of the milk nutrition period. After weaning oral insulin effect on the intestinal carbohydrate digestion and absorption was absent. These data show oral insulin keeps its biological activity in the intestinal cavity and they suggest involvement of milk insulin in the hydrolysis and absorption of carbohydrates in the small intestine.