[Application of extended hyperinsulinemic euglycemic clamp in the assessment of insulin sensitivity in obese individuals with glucose intolerance].
OBJECTIVE
To study the changes of insulin sensitivity in individuals with impaired glucose tolerance and diabetes and the relationship between insulin sensitivity and over weight/obesity (OW/OB) .


METHODS
Fifty-two individuals were divided into 4 groups according to WHO diagnostic criteria of obesity (1998) and diabetes (1999): normal weight with normal glucose tolerance (NW-NGT) group, OW/OB with normal glucose tolerance (OW/OB-NGT) group, OW/OB with impaired glucose tolerance (OW/OBIGT) group and OW/OB with diabetes mellitus (OW/OB-DM) group. Individuals in OW/OB-NGT group were further classified into 3 subgroups: over weight subgroup, mild obesity subgroup, and mediate obesity subgroup. Abdominal fat area was measured with magnetic resonance imaging. Visceral obesity was defined as intra-abdominal fat area over 100 cm(2). All subjects with NGT were divided into visceral obesity (VA) group and non-visceral obesity ( Non-VA) group. Extended hyperinsulinemic euglycemic clamp was performed to assess the peripheral tissue insulin sensitivity in all subjects.


RESULTS
The rates of insulin mediated glucose disappearance (Rd) were (3. 25+/-0. 13) mg x kg (-1) min (-1) in OW/OB-NGT group, (3. 06+/-0. 26) mg x kg(-1) x min(-1) in OW/OB-IGT group, and (3.19+/-0.44) mg x kg(-1) x min (-1) in OW/OB-DM group, which were significantly lower than that in NW-NGT group [ (5. 86+/-0. 65) mg x kg (-1) min (-1) ] (P < 0. 05, P < 0.01). The Rd in over weight subgroup [(3.50+/-0. 19) mg kg(-1) x min(-1) ] , mild obesity subgroup [(3. 03+/-0. 13) mg x kg (-1) min(-1)] , and mediate obesity subgroup [(2. 75 +/-0. 24) mg x kg (-1) min(-1)] were significantly lower than that of NW-NGT group (P <0. 05, P <0. 01). The Rd [ (2. 97+/-0. 12) mg kg(-1) x min(-1) vs (4.55+/-0.43) mg x kg(-1) x min(-1)] and glucose oxidation [(1.47 +/-0. 19) mg x kg(-1) min(-1) vs (2.24 +/-0. 19) mg kg(-1) x min(-1) in VA group were significantly decreased than that in non-VA group (P < 0. 05, P < 0. 01). Body mass index, waist and hip ratio, waist circumference, and intra-abdominal fat area were negatively correlated with Rd, respectively (P < 0. 01). Multiple regression analysis showed that body mass index, intra-abdominal fat area and abdominal subcutaneous fat area were the main risk factors of insulin sensitivity.


CONCLUSIONS
Insulin sensitivity decreased in OW/OB individuals with or without hyperglycemia. Insulin sensitivity is lower in subjects with visceral obesity. Total body fat and abdominal fat are the main risk factors of insulin sensitivity.
Bao
Yu-qian
YQ
Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
Jia
Wei-ping
WP
Chen
Lei
L
Lu
Jun-xi
JX
Zhu
Min
M
Lu
Wei
W
Xiang
Kun-aan
KA
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D005260:Female; D015309:Glucose Clamp Technique / Q000379:methods; D018149:Glucose Intolerance / Q000209:etiology; D006801:Humans; D007333:Insulin Resistance; D050152:Intra-Abdominal Fat / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D050507:Subcutaneous Fat, Abdominal / Q000378:metabolism