Difference between Insulin Resistance & Diabetes

Difference betweeen Insulin Resistance & Diabetes

Insulin resistance and type 2 diabetes are two interconnected conditions that are associated with glucose metabolism.  These two conditions are characterized by elevated blood glucose levels.  In insulin resistance, the blood glucose levels are not high enough to be classified as type 2 diabetes but if left untreated can progress into diabetes (Saltiel & Kahn, 2001). 
  
Insulin resistance is reduced insulin effects on peripheral tissues and this leads to an impaired ability to clear glucose from the blood via the GLUT-4 transporter protein(Stannard & Johnson, 2003).  During insulin resistance, the pancreatic B-cells overproduce insulin in response to a rise in blood glucose.   Insulin resistance is an epidemic in the United States and associated with body adiposity (Yamauchi, et al., 2001).  Due to the direct association between insulin resistance and high fat storage, the accumulation of visceral fat and intramyocellular triglyceride content (IMTG) in the body directly impairs insulin sensitivity in the pancreas, skeletal muscle, and liver (Stannard & Johnson, 2003). Insulin does not respond with lipoprotein lipase (LPL) and fats are not stored in adipocytes, but are instead accumulated in vital organs.  


Type 2 diabetes mellitus is characterized by the combination of insulin resistance and the decreased functioning of pancreatic B-cells that secrete insulin in response to glucose (Li & Hui, 2009).  The pancreas continues to secrete insulin but the insulin-signaling pathway does not work properly and the GLUT-4 transporter protein does not clear glucose from the blood.  This disrupts cell functions and ultimately leads to cell death (Unger & Orci, 2001).  At the cellular level, the regulation of carbohydrates, lipids and proteins is inhibited and this produces elevated fasting and postprandial glucose and lipid levels (Saltiel & Kahn, 2001).