Fat Mass Localization Alters Fuel Oxidation during Exercise in Normal Weight Women.
ABSTRACT PURPOSE: Abdominal and lower body fat mass tissues exhibit particular metabolic profiles at rest and during exercise. However data are missing in normal weight women during exercise. The purpose of this study was to investigate the impact of low (LA/LB) and high (HA/LB) abdominal to lower body (A/LB) fat mass ratio on metabolic and hormonal responses during exercise in premenopausal normal weight women. METHODS: After preliminary testing (VO2max and body composition assessment), substrate oxidation (Respiratory Exchange Ratio, lipid and carbohydrate oxidation rates), metabolic (glycerol, free fatty acids, glucose) and hormonal (insulin, growth hormone, atrial natriuretic peptide, adrenaline and noradrenaline) responses were determined during exercise (45 min at 65% of VO2max) in 21 premenopausal normal weight women (10 HA/LB women vs 11 LA/LB women). RESULTS: Waist circumference was significantly higher in HA/LB women compared with LA/LB women (p<0.01). No difference in other anthropometric characteristics, VO2max and resting blood values was observed between the two groups. LA/LB subjects exhibited greater lipid oxidation rates compared with HA/LB women during exercise (p<0.01). This occurred with lower plasma insulin (p<0.05) and glucose (p<0.05) concentrations and higher plasma free fatty acids (p<0.05), glycerol (p<0.05), growth hormone (p<0.05), atrial natriuretic peptide levels (p<0.01) during exercise in the LA/LB group compared with the HA/LB group. CONCLUSION: The present study demonstrated that LA/LB women exhibited an increase in whole-body lipid mobilization and utilization during exercise compared with HA/LB counterparts. This greater reliance on lipid as fuel metabolism during exercise could be explained by substrate availability and metabolic and hormonal responses. It appeared that LA/LB women exhibited greater metabolic flexibility during an exercise bout of 45 min at 65% of VO2max on cycle ergometer.
- [show abstract] [hide abstract]
ABSTRACT: To investigate the association between regional fat mass (FM) and insulin resistance and dyslipidaemia in obese women and men. Body composition was measured by dual-energy X-ray absorptiometry (DXA) in 109 obese women and 113 obese men. Insulin resistance was measured by (HOMA-IR); insulin sensitivity was estimated by metabolic clearance rate (MCRestOGTT) and insulin secretion by HOMAsecr. Serum lipids were assessed. In women, leg FM was negatively (favourably) associated with HOMA-IR and cholesterol/HDL-cholesterol ratio (p<0.05). Trunk FM was positively (unfavourably) associated with HOMA-IR. Leg/trunk FM ratio was negatively associated with HOMA-IR (p<0.001), cholesterol/HDL-cholesterol ratio (p<0.001) and triglycerides (p<0.01); positively (favourably) with MCRestOGTT (p<0.01) and HDL-cholesterol (p<0.05). No associations were found in men. In women, multiple regression analysis demonstrated that leg/trunk FM ratio was the only explanatory FM for HOMA-IR and MCRestOGTT (R(2) = 0.23 and R(2) = 0.13, respectively; p<0.001), but postmenopausal status was also of importance (R(2) = 0.23, p = 0.019 and R(2) = 0.29, p = 0.015, respectively). Leg FM has a favourable influence on insulin resistance and dyslipidaemia in obese women, but not demonstrated in this cohort of obese men.Scandinavian journal of clinical and laboratory investigation 10/2008; 69(2):181-9. · 1.38 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: To establish a unified working diagnostic tool for the metabolic syndrome (MetS) that is convenient to use in clinical practice and that can be used world-wide so that data from different countries can be compared. An additional aim was to highlight areas where more research into the MetS is needed. The International Diabetes Federation (IDF) convened a workshop held 12-14 May 2004 in London, UK. The 21 participants included experts in the fields of diabetes, public health, epidemiology, lipidology, genetics, metabolism, nutrition and cardiology. There were participants from each of the five continents as well as from the World Health Organization (WHO) and the National Cholesterol Education Program-Third Adult Treatment Panel (ATP III). The workshop was sponsored by an educational grant from AstraZeneca Pharmaceuticals. The consensus statement emerged following detailed discussions at the IDF workshop. After the workshop, a writing group produced a consensus statement which was reviewed and approved by all participants. The IDF has produced a new set of criteria for use both epidemiologically and in clinical practice world-wide with the aim of identifying people with the MetS to clarify the nature of the syndrome and to focus therapeutic strategies to reduce the long-term risk of cardiovascular disease. Guidance is included on how to compensate for differences in waist circumference and in regional adipose tissue distribution between different populations. The IDF has also produced recommendations for additional criteria that should be included when studying the MetS for research purposes. Finally, the IDF has identified areas where more studies are currently needed; these include research into the aetiology of the syndrome.Diabetic Medicine 06/2006; 23(5):469-80. · 3.24 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The expression of beta-adrenoceptors (BAR) was investigated in abdominal and gluteal fat cells of 32 nonobese men and women using radioligand binding and RNA excess solution hybridization. In both sexes the number of BAR binding sites was about twice as high in abdominal as in gluteal fat cells (P less than 0.01). Northern blot analysis of total RNA from adipose tissue showed hybridization of the BAR1 probe to an mRNA species of about 2.5 kb and of the BAR2 probe to an mRNA species of approximately 2.2 kb. The steady-state mRNA levels of BAR 1 and BAR 2 were also about twice as high in abdominal as in gluteal adipocytes of men and women (P less than 0.01). In abdominal fat cells the mRNA levels were approximately 45 and 30 molecules/cell for BAR1 and BAR2, respectively. There were no regional or sex variations in BAR 1 and BAR 2 mRNA stability. The apparent half-life of mRNA for both receptor subtypes was approximately 6 h in both regions. The mRNA levels for beta actin did not differ between the two regions in either sex. Thus, differences in expression of the genes encoding for BAR 1 and BAR 2 can explain why abdominal fat cells have more BAR than gluteal fat cells. This variation in gene expression may be a molecular mechanism underlying the well known regional differences in catecholamine-induced lipolysis activity between central and peripheral adipose tissue.Journal of Clinical Investigation 12/1990; 86(5):1595-600. · 12.81 Impact Factor