Type 2 diabetes mellitus is an increasingly common disorder of carbohydrate
and lipid metabolism. Approximately 16 million individuals in the United S
tates have diabetes, and 800,000 new cases are identified each year. Two im
portant characteristics of this disease are insulin resistance, the failure
of peripheral tissues, including liver, muscle, and adipose tissue, to res
pond to physiologic doses of insulin, and failure of pancreatic 13-cells to
properly secrete insulin in response to elevated blood glucose levels. Obe
sity is a significant risk factor for the development of type 2 diabetes me
llitus. Recent observations of extremely lean, lipoatrophic models have rev
ealed a similar predisposition to developing diabetes. Although it may seem
paradoxical that both increased adiposity and severely reduced fat mass ca
use diabetes, a common pathophysiologic process in fat may be responsible f
or the predisposition to develop hyperglycemia in both conditions. This rev
iew will focus on the important role of adipose tissue dysfunction in the p
athogenesis of diabetes, and on insights gained through the application of
microarray technology to analyze adipocyte gene expression.