Beneficial effects of insulin-like growth factor I on epithelial structure and function in parenterally fed rat jejunum

BACKGROUND & AIMS: The functional significance of intestinal hyperplasia stimulated by insulin-like growth factor (IGF)-I is unclear and has not been studied in a model of mucosal atrophy induced by total parenteral nutrition (TPN). The aim of this study was to determine how IGF-I affects intestinal structure and epithelial function in the absence of luminal nutrition caused by TPN. METHODS: Rats were maintained with TPN with or without IGF-I (800 micrograms/day), and jejunal histology and epithelial ion transport were measured after 5 days. In a third TPN group without IGF-I, a short-term dose of IGF-I was added during in vitro flux chamber experiments. RESULTS: Rats given TPN with IGF-I had greater jejunal mucosal weight, greater protein and DNA content, and increased villus height and crypt depth compared with rats given TPN only. TPN increased ionic permeability and ion transport responses to secretory and absorptive agents. IGF-I in vivo reversed most of these changes; IGF-I in vitro enhanced sodium-dependent glucose absorption but had no other effects. CONCLUSIONS: Coinfusion of recombinant human IGF-I with TPN solution stimulates intestinal hyperplasia and attenuates transport changes induced by TPN. The latter effect seems to be primarily associated with the growth state of the epithelium. (Gastroenterology 1996 Dec;111(6):1501-8)