Non-insulin-dependent diabetes mellitus (NIDDM)' is a metabolic
disease that affects -5% of the population of the Western
world. NIDDM is characterized by hyperglycemia in both the
fed and fasted states and is predominantly associated with obesity.
The disease is manifested by defects in both insulin secretion
from the pancreas and insulin action in peripheral target
tissues (i.e., liver, skeletal muscle, and adipose tissue). Skeletal
muscle is the major site of post-prandial peripheral glucose
disposal, and muscle from NIDDM patients displays markedly
impaired glucose uptake in response to insulin, although the
precise nature of the defect is unknown (1-3). The defect in
glucose transport cannot be explained by a simple reduction
in the level of gene expression of the major muscle glucose
transporter isoform (GLUT4), as little or no reduction in skeletal
muscle GLUT4 content has been found in NIDDM patients
(3-6). Several lines of evidence suggest that elevated glucose
levels directly affect insulin sensitivity in target tissues and
contribute to the dire long-term diabetic complications such as
cardiovascular disease, retinopathy, neuropathy, and nephropathy