Adipocyte

Adipocytes are the cells that primarily compose adipose tissue, specialized in storing energy as fat.

Description
There are two types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT), that are also known as white fat and brown fat respectively. Consequently, these two tissues are made up of two types of fat cells.


 * White fat cells contain a large lipid droplet surrounded by a ring of cytoplasm. The nucleus is flattened and located on the periphery. The fat stored is in a semi-liquid state, and is composed primarily of triglycerides and cholesterol ester. White fat cells secrete resistin, adiponectin and leptin.


 * Brown fat cells are polygonal in shape. Unlike white fat cells, these cells have considerable cytoplasm with lipid droplets scattered throughout. The nucleus is round, and, although eccentrically located, it is not in the periphery of the cell. The brown color comes from the large quantity of mitochondria. Brown fat is also known as “baby fat,” and is used to generate heat.

Lineage
Although the lineage of adipocytes is still unclear, Preadipocytes are undifferentiated fibroblasts that can be stimulated to form adipocytes.

Mesenchymal stem cells can differentiate into adipocytes, connective tissue, muscle or bone.

Areolar connective tissue is composed of adipocytes.