Table 1.
Simplified Scheme of Physiological Roles of Components of the GH System in Body Size and Body Function
| Role | Component of the GH System |
|---|---|
| Body size | |
| Stature | Pituitary GH and circulating IGF-1 |
| Amount of fat | |
| Amount of muscle | |
| Amount of bone | |
| Body function | |
| Brain function | |
| Reproduction | |
| Immune function | Pituitary GH and circulating IGF-1 |
| Voice | Extrapituitary GH |
| Teeth | Tissue growth factors |
| Feeding | IGF-1/IGF-2 |
| Sense organs | |
| Rapid eye movement sleep | |
| Somatotroph expansion | GHRH |
| Non–rapid eye movement sleep | |
| Enteroendocrine connections | Ghrelin and somatostatin |