Liver-derived insulin-like growth factor I (IGF-I) is the principal source of IGF-I in blood but is not required for postnatal body growth in mice

AUTOR(ES)

Sjögren, Klara

FONTE

The National Academy of Sciences

RESUMO

The body growth of animals is regulated by growth hormone and IGF-I. The classical theory of this regulation is that most IGF-I in the blood originates in the liver and that body growth is controlled by the concentration of IGF-I in the blood. We have abolished IGF-I production in the livers of mice by using the Cre/loxP recombination system. These mice demonstrated complete inactivation of the IGF-I gene in the hepatocytes. Although the liver accounts for less than 5% of body mass, the concentration of IGF-I in the serum was reduced by 75%. This finding confirms that the liver is the principal source of IGF-I in the blood. However, the reduction in serum IGF-I concentration had no discernible effect on postnatal body growth. We conclude that postnatal body growth is preserved despite complete absence of IGF-I production by the hepatocytes.

Documentos Relacionados

• The Role of Liver-Derived Insulin-Like Growth Factor-I
• Antioxidant effects of insulin-like growth factor-I (IGF-I) in rats with advanced liver cirrhosis
• Monoclonal antibody to the type I insulin-like growth factor (IGF-I) receptor blocks IGF-I receptor-mediated DNA synthesis: clarification of the mitogenic mechanisms of IGF-I and insulin in human skin fibroblasts.
• Granulosa cell-derived insulin-like growth factor (IGF) binding proteins are inhibitory to IGF-I hormonal action. Evidence derived from the use of a truncated IGF-I analogue.
• Interactions between insulin-like growth factor-I (IGF-I) and the renin-angiotensin system in follicular growth and ovulation.