Growth hormone effects in intestinal adaptation after massive bowel resection in the suckling rat

Background: Massive small bowel resection provokes intestinal malabsorption that leads to diminished growth in the suckling rat. Growth hormone is one of the several factors that can enhance the adaptive response of the intes tines in the adult rat; however, whether it also enhances postresection int estinal adaptation in the suckling rat, thus reducing the adverse effects o f resection on growth, is still unclear. Methods: Seventy-four 30-day-old suckling Wistar rats underwent 80% midgut bowel resection, laparotomy (sham operation), or no surgery. They were trea ted with either growth hormone or saline for 15 days and studied 15 or 45 d ays after surgery. Body weight was monitored and samples of bone and intest inal mucosa were obtained at the end of the study period for analysis. Results: Resected rats lost body and bone weight regardless of growth hormo ne administration. Bowel resection provoked significant increases in the pr oliferation and size of the intestinal mucosa. Growth hormone significantly , but just barely, increased crypt height and mucosal mass at day 15 after surgery, but not at day 45. Lengthening of the intestines was the main effe ct of growth hormone. Conclusions: The relatively small adaptive response of intestines to growth hormone is insufficient to promote body growth after intestinal resection in the suckling rat. This response is lower than that in older rats and may reflect an age-related differential response to growth hormone.