Inclusion Criteria: Study subjects will include those with: type 2 diabetes mellitus defined according to the 1997 ADA criteria and age of 18 years or greater. We will sample from three different patient populations: (1) 96 individuals who have HbA1c < 8%, and no evidence of chronic renal insufficiency (a serum creatinine <1.3mg/dl for women and <1.5mg/dl for men). (2) 96 individuals with HbA1c > 8%, and no evidence of chronic renal insufficiency, and (3) 96 individuals with evidence of chronic renal insufficiency (a serum creatinine >1.3mg/dl for women and >1.5mg/dl for men, but who have not yet progressed to dialysis), regardless of HbA1c level.