What is the Antilipolytic action of insulin?
What is the Antilipolytic action of insulin?
Insulin action on adipocytes induces two major metabolic effects: stimulation of glucose transport and inhibition of lipolysis. Previously, we have shown that incubated isolated adipocytes from starved (S), and streptozotocin-treated diabetic (D) rats show insulin resistance on glucose transport.
What is Antilipolytic?
Insulin is the major antilipolytic hormone and its decrease is the major factor in insuring the increased availability of the fatty acids needed for energy metabolism during starvation. Adipose tissue contains a hormone-sensitive lipase that is sensitive to the state of its phosphorylation.
Why insulin is an anti lipolytic hormone?
Insulin promotes lipid synthesis and storage, reduces plasma FFAs, and inhibits the catabolism of lipids and FFA oxidation. Insulin is the most important hormone that inhibits lipolysis.
How does insulin affect lipolysis?
One of the basic functions of insulin in the body is to inhibit lipolysis in adipocytes. Recently, we have found that insulin inhibits lipolysis and promotes triglyceride storage by decreasing transcription of adipose triglyceride lipase via the mTORC1-mediated pathway (P.
What is the first step in lipolysis?
The first step and the rate-limiting step of lipolysis is carried out by adipose triglyceride lipase (ATGL). This enzyme catalyzes the hydrolysis of triacylglycerol to diacylglycerol.
What are the effects of insulin deficiency?
Dysfunction. Insulin deficiency results in hyperglycaemia. The effects of hyperglycaemia are salt and water depletion due to an osmotic diuresis, weight loss, tiredness, vomiting, hypotension, infections, hyperventilation (due to ketoacidosis) and impaired conscious level and coma.
How does insulin stimulate lipogenesis?
Insulin promotes lipogenesis, thereby resulting in the storage of triglycerides in adipocytes and of low-density lipoproteins (LDL) in hepatocytes. Insulin stimulates lipogenesis by activating glucose import, regulating the levels of glycerol-3-P and lipoprotein lipase (LPL).
What does the brain use for energy during starvation?
During starvation, the brain must be supplied with fuel in the form of glucose or ketone bodies. During starvation, most tissues utilise fatty acids and/or ketone bodies to spare glucose for the brain.
What is the antilipolytic action of insulin on fat cells?
The inhibition by high concentrations of lipolytic agents on the stimulation by insulin of glucose metabolism and leucine incorporation into protein appears to be due to accumulation of intracellular free fatty acids. Our results suggest that the antilipolytic action of insulin may also be unrelated to effects of insulin on cyclic AMP accumulation.
How does theophylline reverse the antilipolytic action of insulin?
The addition of theophylline to cells incubated with norepinephrine abolished the antilipolytic and other actions of insulin. The addition of dibutyryl cyclic AMP or fatty acids mimicked the effects of lipolytic agents on insulin action except that fatty acids stimulated lactate formation.
What are the effects of insulin on adipose tissue?
The hypothesis that the effects of insulin on adipose tissue metabolism are secondary to inhibition of cyclic AMP accumulation was investigated using isolated rat white fat cells.
What does insulin do to white fat cells?
Under conditions in which insulin inhibited the lipolytic action of catecholamines it did not affect the accumulation of total cyclic AMP, labeled cyclic AMP or ATP in white fat cells. The stimulation of leucine incorporation into protein and of [1- 14 C] glucose oxidation by insulin was abolished by high concentrations of theophylline.