Lumbar sympathectomy caused greater increase in skeletal muscle blood flow in response to both insulin and IGF-1 when hypoglycemia occurred. But when hypoglycemia was prevented, IGF-1 induced increase in blood flow was suppressed in sympathetic denervated iliac artery. We concluded that insulin and IGF-1 have both similar and distinct effects on cardiovascular system and sympathetic nervous system. They both may act directly on vasculature to elicit vasodilation thus decrease MAP Insulin can selectively increase sympathetic nerve activity, while IGF-1 decreases sympathetic nerve activity.
Zhengbo Duanmu, Wayne State University