ORALLY-ADMINISTERED IGF-I INCREASES INTESTINAL MUCOSAL GROWTH IN FORMULA-FED NEONATAL PIGS

Our objective was to determine the potentially anabolic effects of ora lly administered recombinant human insulin-like growth factor I (rhIGF -I) on small intestinal growth in formula-fed neonatal pigs. Unsuckled neonatal pigs received formula or formula containing added rhIGF-I (3 .5 mg . kg(-1). day(-1)) from birth to 4 days of age. Pigs in both gro ups were fed 30 ml/kg formula every 2 h on day 1 and then every 4 h on days 2-4, and blood was sampled daily. Oral administration of rhIGF-I to formula-fed neonatal pigs increased small intestinal weight, prote in, and DNA content, but not length. Jejunal and ileal villus height, but not crypt depth or muscularis thickness, also were increased by or al rhIGF-I administration. Neither the circulating concentration of IG F-I nor the IGF-binding proteins differed between control and oral rhI GF-treated pigs, suggesting that the absorption of orally administered rhIGF-I from the intestinal lumen into the peripheral circulation was limited. Our results demonstrate that oral administration of rhIGF-I during the first 4 days after birth significantly increased small inte stinal mucosal growth in formula-fed neonatal pigs. These results sugg est that oral administration of rhIGF-I may be a viable therapeutic ap proach to enhance intestinal growth in neonates.