Mouse models of IGF-I deficiency generated by gene targeting.

Abstract

Insulin-like growth factor-I (IGF-I) is a pleiotropic hormone synthesized in a wide variety of cell types. As its name suggests, it is highly homologous to insulin and has many similar growth promoting effects. IGF-I is believed to be the major anabolic mediator of growth hormone action. A second insulin-like growth factor (IGF-II) is expressed at high levels in the fetus. IGF-II is homologous to IGF-I and interacts with the IGF-I (type 1) receptor as well as its own (type 2) receptor. Targeted manipulation of the mouse genome enables dissection of gene function in the context of the whole animal. We have generated strains of mice deficient in IGF-I production by homologous recombination that demonstrate important roles for IGF-I in both pre- and postnatal development.