Which are actions of insulin-like growth factor 1?
Insulin-like growth factor-I (IGF-I) is closely related to insulin but has distinct metabolic actions. IGF-I is an important stimulant of protein synthesis in muscle, but it also stimulates free fatty acid use.
What does high insulin-like growth factor 1 mean?
Elevated IGF-1 and GH may indicate acromegaly in adults. Increased levels of GH and IGF-1 are normal during puberty and pregnancy; during the latter, serum IGF-1 increases on average almost 2-fold. Otherwise, increased levels are most frequently due to pituitary tumors (usually benign).
How is insulin a growth factor?
There are several pathways by which insulin can act as a fetal growth factor. First, it may alter cellular nutrition to increase nutrient uptake and utilization. Second, insulin may exert a direct anabolic action via either the insulin or type I IGF receptor.
How does IGF-1 affect insulin?
IGF-I leads to an increase in peripheral glucose uptake and a decreased production of hepatic glucose causing better insulin sensitivity (2,23). Furthermore, low IGF-I serum concentrations were related to a higher anthropometric status, which in turn is related to insulin resistance.
How does insulin affect IGF-1?
Insulin resistance is highly correlated to obesity and high insulin levels as insulin stimulates hepatic IGF-I synthesis (34) and increases the fraction of circulating free IGF-I by downregulating hepatic synthesis of IGFBP-1 and, to a lesser extent, hepatic secretion of IGFBP-2 (35,36).
Where is insulin-like growth factor produced?
Insulin-like growth factor I (IGF-I) is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes.
Is IGF-1 the same as insulin?
Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults.