Genetic selection for insulin-like growth factor-1 in growing mice is associated with altered growth

Abstract

Substantial responses in the 6-week and mature body-weights of mice occurred after 7 generations of selection for or against plasma levels of Insulin-like Growth Factor-1 (IGF-1). Plasma levels of IGF-1 were also significantly different after 7 generations of selection (high line = 8 5 ± 2 ng/ml, low line = 5 8 ± 2 ng/ml). The average 6-week weight in the line selected for high plasma IGF-1 was 22.5 ± 0.2 g compared with 18.5 ±.2 g in the low plasma IGF-1 line, after 7 generations of selection. The difference between lines was maintained at 20 weeks of age. These data provide further evidence for the roles of IGF-1 in the regulation of somatic growth and as a mediator of a genetic component of growth. © 1988 by The Endocrine Society.