The Insulin-Like Growth Factor System and Nutritional Assessment

Table 1

The insulin-like growth factor binding proteins (IGFBPs).

IGFBP	(kDa)	Relative affinity for IGFs	Possible functions
1	25		Inhibition of growth-promoting actions of IGFs and inhibition of insulin-like actions, integrin binding, glucose homeostasis
2	31		Stimulation of splenic growth, suppression of IGF bioactivity, cell surface binding, mitogenic for some cell types
3	29		Inhibition of IGF actions, induction of apoptosis
4	26		Inhibition or enhancement of IGF actions, inhibition of ovarian steroidogenesis, regulation of bone formation
5	28		Localises IGFs in extracellular matrix and bone, regulation of IGF bioavailability
6	23		Inhibition of actions of IGF-II