Human adipose stromal cells provide an excellent model for studying a variety of metabolic processes in an in vitro system These are normal cells derived from subcutaneous or omental adipose tissue. Under specific culture condition, they will differentiate without replication into cells resembling mature adipocytes or will replicate, become confluent, and grow in subculture. The initial observation that the stromal vascular fraction of human omental adipose tissue contained a fibroblast-like cell that was a possible adipocyte precursor was made by Poznanski et al (1 ). Subsequent studies demonstrated enzymological and morphological properties that developed during differentiation (2 –4 ). The primary interest has focused on the conditions required to stimulate these cells to differentiate into adipocytes, which can accumulate lipid and possess the enzymes involved in lipogenesis, including glycerol-3-phosphate dehydrogenase (GPDH) and lipoprotein lipase (LPL)