Effect of urogastrone on intestinal regeneration is dose-dependent.

Urogastrone (UG) increases the rate of intestinal regeneration in intestinal defects patched with adjacent serosal surfaces by increasing the rate of epithelial cell migration and proliferation. It also inhibits contraction of the patched intestinal defect. The purpose of this study was to determine the effect of the dose of UG on these processes. Twenty male New Zealand white rabbits (1.9-2.9 kg) had 2 x 5 cm ileal defects patched with adjacent caecal serosal surface. Group I (n = 6) served as the control group. Group II (n = 5), Group III (n = 5) and Group IV (n = 4) received UG 0.15, 1.5 and 4.5 micrograms/kg/h i.v. via mini-osmotic pumps. Seven days after patching, both epithelialization of the patched defect and neomucosal surface area were significantly increased by UG and the increases were dose-dependent. Contraction was not inhibited by the lowest dose of UG but was diminished by 1.5 micrograms/kg/h. Proliferative activity in both neomucosa and adjacent normal mucosa were increased in UG-treated animals with the greatest increase in rabbits receiving 1.5 and 4.5 micrograms/kg/h UG. The effect of UG on both epithelialization and contraction of patched intestinal defects is dose-dependent. Since the lowest dose of urogastrone increased epithelialization without increasing proliferative activity, stimulated cell migration appears to be the earliest effect of UG.