Comparison of the effects of concanavalin-A and epidermal growth factor onepithelial cell proliferation in the rat intestine

Background: Concanavalin-A, the lectin present in Jack beans, binds to mann ose- and glucose-containing residues and can interact with the epidermal gr owth factor receptor and moderate cell proliferation in vitro. Aim: To compare the actions of concanavalin-A and epidermal growth factor o n the gastrointestinal tract in vivo. Methods: Rats maintained on total parenteral nutrition were given intragast ric concanavalin-A, intravenous epidermal growth factor or concanavalin-A a nd epidermal growth factor. Cell proliferation and crypt fission were assay ed in 'micro-dissected' crypts. Results: Concanavalin-A and epidermal growth factor both significantly elev ated proliferation in the small intestine and colon. No significant interac tion between the effects of these two agents was seen, except in the mid sm all intestine where there was a synergistic interaction. Concanavalin-A had no effect on crypt branching. Epidermal growth factor significantly reduce d branching in the distal small intestine and mid colon. Conclusion: The effects of the two agents appeared to be separate, except i n the mid small intestine where they were additive. This is in marked contr ast with the actions reported in vitro, where concanavalin-A is a powerful inhibitor of epidermal growth factor-induced cell proliferation. Concanaval in-A thus has potential for enhancing the functions of the small intestine.