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

The residual small bowel undergoes profound adaptive alterations after surg ical resection. GH is considered to have a role in regulation of these adap tive changes, but its precise role is unknown. We investigated the role of GH by studying the response to intestinal resection in rats with isolated G H deficiency. Spontaneous dwarf rats, a strain of rats with congenital isol ated GH deficiency, underwent 60% resection of the small intestine and para meters of the response of the intestinal remnant were compared with age-mat ched GH-deficient rats undergoing transection, GH-normal rats undergoing 60 % resection, and non-manipulated GH-normal rats. Deficiency of GH did not i nhibit hyperplasia of the mucosal mass of the intestinal remnant. indicatin g that GH is not required for regulation of this aspect of the adaptive res ponse. However, GH deficiency resulted in lack of accumulation of mucosal p rotein, including lack of accumulation of digestive hydrolases. In addition , GH deficiency resulted in alterations in processing of digestive hydrolas es of the distal intestine, indicating that GH may have region-specific eff ects on small intestinal function. We conclude that GH is required for the normal expression of specific components of the adaptive response to massiv e small intestinal resection, but not for all aspects. The aspects that req uire GH appear to involve protein synthesis and processing.