Is polyamine synthesis involved in the proliferative response of the intestinal epithelium to urogastrone-epidermal growth factor?

1. Intestinal epithelial cell proliferation was measured in rats maintained on total parenteral nutrition (TPN), in TPN rats given 300 micrograms of recombinant human epidermal growth factor (urogastrone-epidermal growth factor, URO-EGF) day-1 kg-1, and in further groups given URO-EGF and difluoromethylornithine (DFMO), an inhibitor of the enzyme ornithine decarboxylase (ODC). 2. URO-EGF significantly increased intestinal cell proliferation throughout the gastrointestinal tract. The proliferative response of the colon was particularly pronounced. 3. DFMO reduced the proliferative effect of urogastrone in the stomach and small intestine. DFMO also reduced URO-EGF-stimulated intestinal cell proliferation in the colon, but to a lesser extent. 4. It is concluded that ODC is essential for effecting the proliferative response of the stomach and small intestine to URO-EGF, but this role may be less important in the colon.