Enhanced growth of small bowel in transgenic mice expressing human insulin-like growth factor I

Gastroenterology. 1997 Feb;112(2):444-54. doi: 10.1053/gast.1997.v112.pm9024298.


Background & aims: Growth hormone and insulin-like growth factor I (IGF-I) stimulate small bowel growth. The aim of this study was to analyze whether IGF-I mediates enterotrophic actions of growth hormone.

Methods: IGF-I transgenic mice that overexpress an IGF-I transgene driven by the mouse metallothionein I promoter and are growth hormone deficient were compared with wild-type littermates. Growth of small bowel, abundance and localization of messenger RNAs for the IGF-I transgene, and insulin-like growth factor-binding protein 3 were assayed.

Results: Small bowel length and mass were greater in IGF-I transgenic mice than in wild-type mice. Villus height, crypt depth, and crypt cell mitoses were greater in jejunum of transgenics than wild-type mice, but jejunal disacharidase activities were not increased. The transgene was expressed strongly in villus epithelial cells. Insulin-like growth factor-binding protein 3 messenger RNA was localized in the lamina propria. Regional expression of both correlated with the increase in mucosal mass.

Conclusions: Effects of IGF-I overexpression on intestinal length and mucosal mass were similar to effects of growth hormone overexpression observed previously. Excess of IGF-I increased crypt cell proliferation, whereas excess of growth hormone did not increase crypt cell proliferation. IGF-I excess stimulated differentiation of intestinal epithelial cells less effectively than growth hormone excess.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Body Weight
  • Cattle
  • Energy Intake
  • Gene Expression
  • Growth Hormone / genetics
  • Humans
  • Insulin-Like Growth Factor Binding Protein 3 / genetics
  • Insulin-Like Growth Factor I / genetics*
  • Insulin-Like Growth Factor I / metabolism
  • Intestinal Mucosa / growth & development
  • Intestinal Mucosa / physiology
  • Intestine, Small / anatomy & histology
  • Intestine, Small / cytology
  • Intestine, Small / growth & development*
  • Jejunum / metabolism
  • Mice
  • Mice, Transgenic / genetics*
  • Mice, Transgenic / metabolism
  • Mice, Transgenic / physiology*
  • Mitosis
  • Organ Size
  • RNA, Messenger / metabolism
  • Reference Values
  • Tissue Distribution


  • Insulin-Like Growth Factor Binding Protein 3
  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Growth Hormone