The present study evaluated pancreatotrophic factors after massive small bowel resection. Specifically, we examined the role of enteroglucagon in compensatory pancreatic hyperplasia after proximal small bowel resection (PSBR) by using rats fed a fiber-free elemental diet or an elemental diet containing pectin. PSBR increased the net pancreatic weight as well as the protein, DNA, RNA, and amylase contents, and elevated plasma enteroglucagon levels. Pectin addition to the diet provoked a further increase in these parameters and significant positive correlations were found between the plasma enteroglucagon levels and the protein, DNA, and RNA contents of the pancreas. Plasma gastrin and CCK levels were not affected by the small bowel resection. These results indicate that enteroglucagon may exert a potent trophic effect on the pancreas after PSBR.