Premium
Insulin sensitivity is not related to regional fat gain in lean men and women
Author(s) -
Votruba Susanne Breuer,
Jensen Michael D
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a425-d
Subject(s) - medicine , meal , endocrinology , insulin resistance , insulin , weight gain , insulin sensitivity , body fat distribution , body fat percentage , adipose tissue , lean body mass , obesity , body weight
An upper body (UB) fat distribution is correlated with insulin resistance (IR). It is not known whether IR is caused by an UB fat distribution or if IR predisposes to UB fat gain. We recruited 25 lean volunteers to gain ~2 kg of body fat over ~8 weeks. We hypothesized that IR individuals would gain more UB fat than insulin sensitive individuals. At baseline, insulin sensitivity was assessed by 24‐hour insulin AUC over a meal controlled inpatient stay. Meal fat disposal was measured by the meal fat tracer/fat biopsy approach. Participants were grouped into tertiles based on their AUC insulin: least insulin sensitive tertile 1 (T1) = 37,449±2600; middle tertile 2 (T2) = 22,11±3002; most insulin sensitive tertile 3 (T3)= 13,233±2452 uU/ml/24h (mean±sem). At baseline, volunteers in the different tertiles had significantly different % body fat (T1=29±2%, T2=22±2%, and T3=18±2%; P<0.005). The T1 had more upper body subcutaneous (UBSQ) fat at baseline (8.3±0.5 kg) than the T3 (6.1±0.5 kg; P<0.05). Visceral and lower body subcutaneous (LBSQ) fat at baseline did not differ significantly between tertiles. Baseline meal fat storage in LBSQ fat was greater in T1 than T3 (20.9±3.4% vs. 9.0±1.9%, P < 0.05). Changes in regional fat gain as a percentage of total fat gain was not different by tertiles (53.3±2.7%, 8.3±2.0%, and 37.8±1.8%, for UBSQ, visceral, and LBSQ). Baseline insulin sensitivity was not predictive of the proportion of fat gain in the visceral or UBSQ regions. This argues against the hypothesis that insulin resistance results in UB fat gain. The alternative explanation is that those who gain UB fat eventually develop IR. T3 stored the least meal fat in the LBSQ region, suggesting that regional fat depots have differing responses to the prevailing insulinemia, perhaps through regulation of LPL activity.