LM of adipose tissue in which the lipid has ben stained with Sudan Black. Adipose tissue (body fat, or simply fat) is loose connective tissue composed mostly of adipocytes. Adipose tissue is derived from preadipocytes. Its main role is to store energy in the form of lipids, although it also cushions and insulates the body. Far from hormonally inert, adipose tissue has, in recent years, been recognized as a major endocrine organ. Magnification unknown.