Insulinlike growth factors

The IGFs (also termed 'somatomedins'), constitute a family of two closely related (small) polypeptides: IGF-I and IGF-II. As the names suggest, these growth factors bear a strong structural resemblance to insulin (or, more accurately, proinsulin). Infusion of IGF-I decreases circulating

GROWTH FACTORS AND WOUND HEALING Table 10.10 Overview of some of the effects of the IGFs

Promotes cell cycle progression in most cell types

Foetal development: promotes growth and differentiation of foetal cells and organogenesis Promotes longitudinal body growth and increased body weight Promotes enhanced functioning of the male and female reproductive tissue Promotes growth and differentiation of neuronal tissue levels of insulin and glucagon, increases tissue glucose uptake and inhibits hepatic glucose export. IGFs display pluripotent activities, regulating the growth, activation, differentiation (and maintenance of the differentiated state) of a wide variety of cell and tissue types (Table 10.10). The full complexity and variety of their biological activities are only now beginning to be appreciated.

The liver represents the major site of synthesis of the IGFs, from where they enter the blood stream, thereby acting in a classical endocrine fashion. A wide variety of body cells express IGF receptors, of which there are two types. Furthermore, IGFs are also synthesized in smaller quantities at numerous sites in the body and function in an autocrine or paracrine manner at these specific locations. IGF activity is also modulated by a family of IGFBPs, of which there are at least six.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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