Growth Hormone and Insulin Like Growth Factors in Adults with Growth Hormone Deficiency

Abstract

The insulin-like growth factors I and II (IGF-I and IGF-II), which function as both endocrine and paracrine hormones, are of importance for growth throughout life. Growth hormone (GH) starts to stimulate IGF-I expression and growth after birth. In addition, GH more directly mobilises endogenous substrate. The beneficial effects on growth by GH replacement therapy in GH deficient children and pharmacological GH therapy in girls with Turner syndrome and uraemic children are well established. During the last decade beneficial effects of GH therapy on body composition and physical performance in GH deficient adults have been demonstrated in several placebo controlled clinical studies. GH increases lean body mass, body water and bone density concomitantly with a decrease in fat mass. GH therapy has also been discussed as therapy in catabolic conditions of other causes than GH deficiency (GHD). In the future IGF-I but not GH would be the hormone of preference for therapy in patients with genetic or functional defects in the GH receptors.