White adipose tissue

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White adipose tissue (WAT) or white fat is one of the two types of adipose tissue.

 

The other kind is brown adipose tissue.

There are three common macroscopic functions of white adipose tissue: stores food calories, creates a layer of thermal insulation, and provides mechanical protection important for resisting infection and injuries.

Insulin is the principal driver of fuel absorption and storage, with adipose tissue responsible for 5% of insulin mediated glucose uptake and adults who are lean and 20% those who are obese.

 

In healthy, non-overweight people, white adipose tissue composes as much as 20% of the body weight in men and 25% in women. 

 

White adipose tissue cells contain a single large fat droplet, which forces the nucleus to be squeezed into a thin rim at the periphery. 

 

Adipocytes have receptors for insulin, sex hormones, norepinephrine, and glucocorticoids.

White adipose tissue is used for energy storage. 

 

Insulin from the pancreas causes white adipose cells’ insulin receptors to a dephosphorylation cascade that leads to the inactivation of hormone-sensitive lipase. 

 

Glucagon acts on the liver to trigger glycogenolysis and gluconeogenesis, and this action is triggered by adrenocorticotropic hormone (ACTH), adrenaline, and noradrenaline.

 

Fatty acids are taken up by muscle and cardiac tissue as a fuel source.

Glycerol is taken up by the liver for gluconeogenesis.

 

It acts as a thermal insulator, helping to maintain body temperature.

 

The hormone leptin is primarily manufactured in the adipocytes of white adipose tissue.