Abdominal fat distribution and peripheral and hepatic insulin resistance in type 2 diabetes mellitus

Abstract

We examined the relationship between peripheral/hepatic insulin sensitivity and abdominal superficial/deep subcutaneous fat (SSF/DSF) and intra-abdominal visceral fat (VF) in patients with type 2 diabetes mellitus (T2DM). Sixty-two T2DM patients (36 males and 26 females, age = 55 ± 3 yr, body mass index = 30 ± 1 kg/m2) underwent a two-step euglycemic insulin clamp (40 and 160 mU · m−2 · min−1) with [3-3H]glucose. SSF, DSF, and VF areas were quantitated with magnetic resonance imaging at the L4–5 level. Basal endogenous glucose production (EGP), hepatic insulin resistance index (basal EGP × FPI), and total glucose disposal (TGD) during the first and second insulin clamp steps were similar in male and female subjects. VF (159 ± 9 vs. 143 ± 9 cm2) and DSF (199 ± 14 vs. 200 ± 15 cm2) were not different in male and female subjects. SSF (104 ± 8 vs. 223 ± 15 cm2) was greater ( P < 0.0001) in female vs. male subjects despite similar body mass index (31 ± 1 vs. 30 ± 1 kg/m2) and total body fat mass (31 ± 2 vs. 33 ± 2 kg). In male T2DM, TGD during the first insulin clamp step (1st TGD) correlated inversely with VF ( r = −0.45, P < 0.01), DSF ( r = −0.46, P < 0.01), and SSF ( r = −0.39, P < 0.05). In males, VF ( r = 0.37, P < 0.05), DSF ( r = 0.49, P < 0.01), and SSF ( r = 0.33, P < 0.05) were correlated positively with hepatic insulin resistance. In females, the first TGD ( r = −0.45, P < 0.05) and hepatic insulin resistance ( r = 0.49, P < 0.05) correlated with VF but not with DSF, SSF, or total subcutaneous fat area. We conclude that visceral adiposity is associated with both peripheral and hepatic insulin resistance, independent of gender, in T2DM. In male but not female T2DM, deep subcutaneous adipose tissue also is associated with peripheral and hepatic insulin resistance.