It should not be surprising that adequate amount of insulin are necessary for normal growth since insulin is, in all respects, an anabolic hormone. Its stimulatory efects on amino acid uptake and protein synthesis are particularly important with regard to growth.
In addition to this anabolic effect, however, insulin exerts specific growth-promoting effects on cell differentiation and cell division during fetal life. Insulin may also exert this effect during childhood since it cam stumulate the secretion of IGF-I.