K. Sjogren et al., Liver-derived insulin-like growth factor I (IGF-I) is the principal sourceof IGF-I in blood but is not required for postnatal body growth in mice, P NAS US, 96(12), 1999, pp. 7088-7092
Citations number
33
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
The body growth of animals is regulated by growth hormone and IGF-I, The cl
assical theory of this regulation is that most IGF-I in the blood originate
s in the liver and that body growth is controlled by the concentration of I
GF-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 comple
te inactivation of the IGF-I gene in the hepatocytes, Although the liver ac
counts for less than 5% of body mass, the concentration of IGF-I in the ser
um was reduced by 75%, This finding confirms that the liver is the principa
l source of IGF-I in the blood. However, the reduction in serum IGF-I conce
ntration had no discernible effect on postnatal body growth. We conclude th
at postnatal body growth is preserved despite complete absence of IGF-I pro
duction by the hepatocytes.