Regulation and Action of Insulin-Like Growth Factors at the Cellular Level

Proc Nutr Soc. 1990 Oct;49(3):451-8. doi: 10.1079/pns19900053.

Abstract

Present understanding of IGF-1 as a growth factor mediating integration of nutritional-hormonal interactions indicates that IGF-1 acts in both an endocrine mode on distant targets and an autocrine-paracrine mode on local targets. In the liver, the combined presence of GH, insulin, and critical metabolic fuels such as essential amino acids results in increased levels of IGF-1 messenger RNA, increased production of a high-MW IGF-1 precursor, and increased release of IGF-1 into the circulation, permitting action on distant target tissues bearing specific receptors for IGF-1. The net effect is distant amplification of anabolic hormone action via IGF-1 acting in an endocrine mode. In extrahepatic tissues, both 'general' anabolic hormones (insulin and GH) as well as 'specific' hormones (e.g. gonadotropins) acting on a wide variety of targets (including fibroblasts and chondrocytes as well as granulosa and Leydig cells) promote both local secretion of IGF-1 and an increase in IGF-1 receptors. Local actions of IGF-1 then result in a secondary increase in both hormone receptors and hormone responses. The net effect is local amplification of hormone action via IGF-1 acting as a growth factor in an autocrine-paracrine mode.

Publication types

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

MeSH terms

  • Animals
  • Humans
  • Insulin-Like Growth Factor I / physiology
  • Receptors, Cell Surface / metabolism
  • Receptors, Somatomedin
  • Somatomedins / genetics
  • Somatomedins / physiology*

Substances

  • Receptors, Cell Surface
  • Receptors, Somatomedin
  • Somatomedins
  • Insulin-Like Growth Factor I