[Relationships between growth, and plasma growth hormone and growth factors under normal physiological conditions and...

Growth hormone (GH) and somatomedin (Sm) are the main factors of human growth. Sm is GH-dependent, but Sm increase after hGH injection in hypopituitary dwarfs is slow, and preceded by a decrease. The liver and kidneys are the main places of Sm production in vivo, the liver having probably also a regulatory effect. In vitro, GH-dependent production of Sm may be obtained from fibroblasts as well as from liver cells. Sm activates thymidine uptake by cultured human fibroblasts and by activated human lymphocytes, this effect needing cofactors from serum. Discrepant correlations between growth, GH and Sm are found in some pathological situations, such as obesity, craniopharyngioma, celiac disease, infantile malnutrition. Moreover, transferrin, a plasma protein, correlates also with growth.