MICRODIALYSIS ASSESSMENT OF ADIPOSE-TISSUE METABOLISM IN POST-ABSORPTIVE OBESE NIDDM SUBJECTS

Lactate and glycerol turnover is enhanced in obesity and NIDDM. To eva luate the influence of NIDDM on subcutaneous adipose tissue metabolism microdialysis combined with Xe-133 clearance and measurements in arte rialized plasma were carried out using samples of subcutaneous abdomin al fat from nine obese NIDDM subjects (glucose, 7.9 +/- 0.7 mmol L(-1) ) (mean +/- SEM) and nine obese non-diabetic subjects (glucose, 4.9 +/ - 0.1) matched for age, BMI and body fat. After an overnight fast arte rialized plasma levels were 1145 +/- 110 vs. 876 +/- 59 mu mol L(-1) ( P<005) for lactate 75 +/- 10 vs. 66 +/- 8 mu mol L(-1) for glycerol in control group, respectively. The corresponding abdominal subcutaneous interstitial lactate and glycerol concentrations were 1278 +/- 63 vs 1107 +/- 64 mu mol L(-1) and 314 +/- 28 vs. 311 +/- 17 mu mol L(-1), r espectively. However, adipose tissue blood flow in the same region was lower in NIDDM subjects (1.5 +/- 0.2 vs 2.4 +/- 0.3 mL 100 g(-1) min( -1)) (P<0.05). Consequently, apparent subcutaneous lactate and glycero l release, estimated according to Fick, were not statistically differe nt in the two groups (1.8 +/- 0.4 vs 2.4 +/- 0.8 and 2.1 +/- 0.4 vs 3. 1 +/- 0.5 mu mol kg(-1) min(-1) in NIDDM and control subjects, respect ively). Thus, in the post-absorptive state apparent lactate and glycer ol release by the abdominal subcutaneous tissue in obese NIDDM subject s was similar to that in a matched group of obese nea-diabetic control s. The data suggest that no primary defect is evident in adipose tissu e metabolism in well controlled NIDDM subjects.