big IGF-II

(redirected from prohormone form of IGF-II)

big IGF-II

A form of IGF-II which is produced by tumours and stimulates the uptake of glucose by the tumours and by insulin-responsive tissues—e.g., muscle, fat. Hepatic glucose production and insulin secretion are decreased by hypoglycaemia, and by the direct inhibitory effects of big IGF-II on pancreatic beta cells. Big IGF-II also inhibits pituitary growth (hGH) hormone secretion, which in turn decreases the synthesis and secretion of IGF-I and IGF-binding protein 3; decreased IGF-BP3 enhances the effects of IGF-II in the circulation.