Estrogen induces insulin-like growth factor-I expression in the rat uterus

Mol Endocrinol. 1987 Jul;1(7):445-50. doi: 10.1210/mend-1-7-445.


The inability to convincingly demonstrate a mitogenic effect of estrogen on isolated uterine cells in culture suggests that autocrine or paracrine growth factors may be important in the estrogen-induced uterine proliferative response. Here we report that uterine expression of insulin-like growth factor-I (IGF-I), an important mediator of GH action, is increased after 17 beta-estradiol (5 micrograms/100 g bw, ip) administration to ovariectomized prepubertal rats. An increase in uterine IGF-I mRNA abundance, approximately 14-fold above untreated controls, was apparent 6 h after estrogen administration and the level achieved exceeded that seen in the uterus from intact mature rats during diestrus. In contrast to the increase in IGF-I expression in the uterus, no significant change in serum IGF-I concentration or hepatic or renal IGF-I mRNA abundance was demonstrable after 17 beta-estradiol injection of ovariectomized prepubertal rats. The increase in uterine IGF-I expression, was similar in both pituitary-intact and hypophysectomized, ovariectomized rats. We believe this is the first report of induction of IGF-I expression by estrogen in vivo. As such, the finding expands the role and significance of IGF-I as a mediator of growth beyond that related to GH.

Publication types

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

MeSH terms

  • Animals
  • Estradiol / pharmacology*
  • Female
  • Growth Hormone / pharmacology
  • Hypophysectomy
  • Insulin-Like Growth Factor I / biosynthesis*
  • Insulin-Like Growth Factor I / metabolism
  • Nucleic Acid Hybridization
  • Ovariectomy
  • Ovary / physiology
  • Pituitary Gland / physiology
  • RNA / genetics
  • RNA / isolation & purification
  • Radioimmunoassay
  • Rats
  • Rats, Inbred Strains
  • Uterus / drug effects*
  • Uterus / metabolism


  • Estradiol
  • RNA
  • Insulin-Like Growth Factor I
  • Growth Hormone