Explain Brown fat and white adipose tissue - energy balance?
There are two kinds of adipose tissue - Brown Fat is located around the shoulder blades and kidneys, constituting 1-296 of body weight. It is highly vascular which the reason for its brown colour is. It is capable of producing a large amount of heat for cold adaptation by burning of excess energy. 1t is a site for conversion of thyroid hormone, thyroxin, to its biologically active form. . White adipose tissue acts as a cushion to protect abdominal organs and is the fat that accumulates under the skin. Earlier, it was thought that Wm is passive and acts only as a fat storage depot. WN, in fact, is a smart tissue and has a number of functions to perform. It has now been realized that WAT is an endocrine organ, which besides some other factors, secretes a hormone leptin. Leptin seems to have a role to play in reducing appetite or increasing satiety and also in regulation of the energy balance. A deficiency of leptin, therefore, is conducive to obesity. Adipocytes in WAT also have a number of hormone receptors on their cell surfaces. That is why individuals with abdominal obesity are prone to developing insulin resistance which initially causes impaired glucose tolerance and ultimately may cause Diabetes mellitus.