The role of growth hormone in adaptation to massive small intestinal resection in rats

The residual small bowel undergoes profound adaptive alterations after surgical resection. GH is considered to have a role in regulation of these adaptive changes, but its precise role is unknown. We investigated the role of GH by studying the response to intestinal resection in rats with isolated GH deficiency. Spontaneous dwarf rats, a strain of rats with congenital isolated GH deficiency, underwent 60% resection of the small intestine and parameters of the response of the intestinal remnant were compared with age-matched GH-deficient rats undergoing transection, GH-normal rats undergoing 60% resection, and nonmanipulated GH-normal rats. Deficiency of GH did not inhibit hyperplasia of the mucosal mass of the intestinal remnant, indicating that GH is not required for regulation of this aspect of the adaptive response. However, GH deficiency resulted in lack of accumulation of mucosal protein, including lack of accumulation of digestive hydrolases. In addition, GH deficiency resulted in alterations in processing of digestive hydrolases of the distal intestine, indicating that GH may have region-specific effects on small intestinal function. We conclude that GH is required for the normal expression of specific components of the adaptive response to massive small intestinal resection, but not for all aspects. The aspects that require GH appear to involve protein synthesis and processing.