Oral IGF-I enhances nutrient and electrolyte absorption in neonatal pigletintestine

The effect of orally administered insulin-like growth factor-I (IGF-I) on s mall intestinal structure and function was studied in 5-day-old colostrum-d eprived piglets. Human recombinant IGF-I (3.5 mg . kg(-1). day(-1)) or cont rol vehicle was given orogastrically for 4 days. Body weights,jejunal and i leal mucosa wet and dry weights, and serum IGF-I levels were similar in the two groups. Small intestinal villus height and crypt depth and jejunal ent erocyte microvillar dimensions were also similar between groups. Oral IGF-I produced higher rates of jejunal ion transport because of increased basal Na+ absorption. Short-circuit current responses to mucosal addition of D-gl ucose and L-alanine and net transepithelial absorption of 3-O-methylglucose were increased by IGF-I. Carrier-mediated uptake of D-glucose per milligra m in everted jejunal sleeves was greater in IGF-I-treated piglets because o f a significantly greater maximal rate of uptake. We conclude that rates of net Na+ and Na+-dependent nutrient absorption are enhanced in piglets trea ted with oral IGF-I, and this effect is independent of changes in mucosal m ass or surface area.