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 hyperplas ia stimulated by insulin-like growth factor (IGF)-I is unclear and has not been studied in a model of mucosal atrophy induced by total paren teral 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 mu g/day), and jejunal histology and e pithelial ion transport were measured after 5 days. In a third TPN gro up 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 grea ter jejunal mucosal weight, greater protein and DNA content, and incre ased villus height and crypt depth compared with rats given TPN only, TPN increased ionic permeability and ion transport responses to secret ory and absorptive agents. IGF-I in vivo reversed most of these change s; 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 tra nsport changes induced by TPN, The latter effect seems to be primarily associated with the growth state of the epithelium.