The trophic action of growth hormone, insulin-like growth factor-I, and insulin on human duodenal mucosa cultured in vitro.

BACKGROUND: Experimental evidence suggests that hormones may regulate small intestinal adaptation after surgical resection. AIMS: To characterise the effect of recombinant human growth hormone (GH), insulin-like growth factor-I (IGF-I) and insulin on crypt epithelial cell proliferation in the human duodenal mucosa cultured in vitro. PATIENTS: Thirty nine adults had endoscopic duodenal biopsy specimens taken, which were histologically normal and pair matched specimens from each patient acted as their own control.
METHODS: Paired biopsy specimens from patients were cultured in vitro, with or without the addition of GH (0.004 IU/ml), IGF-I (400 ng/ml) or insulin (50 micrograms/ml), alone or in combination. After 22 hours, vincristine sulphate was added to the cultures and three hours later specimens were removed and fixed, and DNA stained by the Feulgen method. Intestinal crypts were microdissected and crypt epithelial cell proliferation determined by estimating mean numbers of accumulated metaphase arrests/crypt present in tests and controls between 22-25 hours of culture.
RESULTS: The addition of GH, IGF-I, and insulin, alone or in combination, significantly increased crypt epithelial cell proliferation in test explants compared with controls. IGF-I was most potent and its trophic effect was modified by insulin.
CONCLUSIONS: GH, IGF-I, and insulin are involved in the regulation of crypt cell proliferation in the human small intestine in vitro and possibly in vivo.