Which of the following is action of insulin -
Ans. is 'b' i.e., Increased glucose uptake in muscle* Insulin is a hypoglycemic and anabolic hormoneImmediate effects of insulin:* Immediate effects of insulin include the effect of insulin on causing glucose and potassium uptake into cells# Insulin stimulates glucose uptake into cells by :* Stimulating GLUT4 transporter upregulation across the membranes of skeletal muscle, cardiac muscle and adipose tissue* Stimulating glucokinase in liver. As glucokinase is stimulated in liver, glucose in liver is converted to glucose 6 phosphate. This reduces glucose level within hepatocytes. This stimulates further glucose uptake into hepatocytes* Pis note, glucose uptake in endothelium, lens, kidney, neurons are insulin independent. This is why, in diabetes, when the insulin availability is low, glucose is not taken up by skeletal muscle, cardiac muscle and adipose tissue. Hence glucose stays back in blood. The excess glucose in blood gets into those cells, which are independent of insulin for glucose uptake. Excess glucose is taken up by endothelium, lens, kidney and neurons and in these cells, it causes glucose toxicity. Glucose toxicity in endothelium causes microvascular and macrovascular complications of diabetes. Glucose toxicity in lens causes cataract. Glucose toxicity in neurons and kidney causes neuropathy and nephropathy.# Insulin stimulates potassium uptake into cells by stimulating sodium potassium ATPaseIntermediate effects of insuin* Intermediate effects of insulin include the effect of insulin on carbohydrate and protein metabolism# Carbohydrate metabolism* Insulin stimulates glycolysis and glycogen synthesis* Insulin inhibits gluconeogenesis and glycogenolysis# Protein metabolism* Insulin stimulates protein synthesis* Insulin inhibits protein catabolismLong term effects of insulin* Long term effects of Insulin include the effect of Insulin on lipid metabolism and growth and multiplication of cells# Lipid metabolism* Insulin stimulates fatty acid synthesis, triacylglycerol synthesis, cholesterol synthesis* Insulin inhibits lipolysis in adipose tissue* Thus, insulin stimulates glucose uptake in skeletal muscle, not in endothelium* Insulin stimulates glycogen synthesis not glycogenolysis* Insulin stimulates glycolysis not gluconeogenesis.
Gluconeogenesis
Increased glucose uptake in muscle
Glycogenolysis
Increased glucose uptake in endothelium
Carbohydrates