White adipose tissue or white fat is one of the two types of adipose tissue found in mammals. The other kind is brown adipose tissue. White adipose tissue is composed of monolocular adipocytes. In humans, the healthy amount of white adipose tissue varies with age, but composes between 6-25% of body weight in adult men and 14-35% in adult women. Its cells contain a single large fat droplet, which forces the nucleus to be squeezed into a thin rim at the periphery. They have receptors for insulin, sex hormones, norepinephrine, and glucocorticoids. White adipose tissue is used for energy storage. Upon release of insulin from the pancreas, white adipose cells' insulin receptors cause a dephosphorylation cascade that leads to the inactivation of hormone-sensitive lipase. It was previously thought that upon release of glucagon from the pancreas, glucagon receptors cause a phosphorylation cascade that activates hormone-sensitive lipase, causing the breakdown of the stored fat to fatty acids, which are exported into the blood and bound to albumin, and glycerol, which is exported into the blood freely. There is actually no evidence at present that glucagon has any effect on lipolysis in white adipose tissue. Glucagon is now thought to act exclusively on the liver to trigger glycogenolysis and gluconeogenesis. The trigger for this process in white adipose tissue is instead now thought to be adrenocorticotropic hormone, adrenaline and noradrenaline. Fatty acids are taken up by muscle and cardiac tissue as a fuel source, and glycerol is taken up by the liver for gluconeogenesis. White adipose tissue also acts as a thermal insulator, helping to maintain body temperature. The hormone leptin is primarily manufactured in the adipocytes of white adipose tissue which also produces another hormone, asprosin. Location and morphology White adipose tissue is most abundant in mammals and its distribution greatly varies among different species. Usually white adipose tissue can be found in two different locations of the body where it is stored: subcutaneous adipose tissue and intra-abdominal adipose tissue. Subcutaneous adipose tissue is directly underneath the skin, while the intra-abdominal adipose tissue surrounds the organs inside the abdomen such as intestine and kidneys. The intra-abdominal adipose tissues covers the thoracic and abdominal cavity. The visceral adipose tissue is part of the intra-abdominal adipose tissue that surrounds the intestine for the most part. White adipose tissue exists mostly as a single adipocytes in the subcutaneous tissue. Development In humans, white adipose