Adipocytes are cells present in adipose tissue, specialized in storing energy as fat. There are two types of adipose tissue (white fat and brown fat) and consequently, two types of adipocytes.

• White adipocyte - These cells contain large lipid vacuoles 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. White adipocyte secrete resistin and leptin.

• Brown adipocyte - These cells are polygonal in shape. Unlike white adipocyte, these cells have considerable cytoplasm with lipid droplets scattered throughout. The nucleus is round and although eccentrically located, they are not in the periphery of the cell. Brown adipocyte

Although the lineage of adipocytes is still unclear, it appears mesenchymal stem cells can differentiate into two types of lipoblasts, one that give rise to white adipocytes and the other to brown adipocytes.