[Growth, somatomedin and nutrition]

The skeletal growth-promoting action of growth hormone appear to be mediated by circulating somatomedins or insulin-like growth factor(s) (IGF), which act directly to promote the proliferation of growing cartilage. The actions of IGF(s) include also insulin-like activity in extraskeletal tissues and mitogenic activity. Serum concentrations of IGF(s) were found to be dependent on hormonal levels and nutritional status and are reduced by malnutrition or dietary restrictions. The actions of somatomedins may be modulated at the tissue level by somatomedins inhibitor, factor that may act to limit growth in conditions of hormonal and/or nutrition deficiency. Plasma concentration of somatomedins are a good marker of acute directional change in nitrogen balance and dietary energy and protein appears to be particularly important for both generation of somatomedins, and their action on growing cartilage. Measurement of somatomedin concentration shows promise as a means for monitoring the response of malnourished children and rats to nutrition repletion.