Metabolic indices in relation to body composition changes during weight loss on Dexfenfluramine in obese women from two South African ethnic groups.
OBJECTIVE
To characterize differences in metabolic indices as well as body composition in two ethnic groups.


METHODS
Eight black and eight white obese urban women were studied.


METHODS
Eight black and eight white obse (BMI > 34) urban women (BW, WW) were matched for age, BMI, WHR, diet and physical activity and investigated before and after 12 weeks of Dexfenfluramine treatment.


METHODS
Anthropometric measurements; Post 75 g OGTT, plasma glucose, insulin and C-peptide levels were done. FFA and lactate levels were done at onset. Skinfold thickness with Harpenden calipers, bio-impedance for analyses of body composition and CT scan for assessment of regional adiposity (at onset and after 3 months).


RESULTS
In the postabsorptive state the WW had significantly higher plasma total cholesterol and triglyceride levels and an unfavourable HDL : total cholesterol ratio. Their FFA levels were significantly lower (324 +/- 51 vs 985 +/- 84 mumol/l; p < 0.0001) and their lactate levels were significantly higher (3045 +/- 245 vs 1938 +/- 358 mumol/l; p < 0.001) as compared with the BW. During a 75 g OGTT the BW had significantly higher glucose levels at 1 h (8.6 +/- 0.8 vs 5.1 +/- 0.4 mmol/l; p < 0.005) and 2 h (7.6 +/- 0.6 vs 4.4 +/- 0.3 mmol/l) but not at fasting. In contrast the BW had lower insulin concentrations (fasting: 77 +/- 9 vs 139 +/- 19 pmol/l; p < 0.04 and 1 h 318 +/- 56 vs 624 +/- 75 pmol/l; p < 0.005), and C-peptide concentrations (fasting: 400 +/- 99 vs 1600 +/- 99 pmol/l; p < 0.000 04, 1 h 1400 +/- 433 vs 5966 +/- 333 pmol/l; p < 0.0007 and 2 h 1266 +/- 333 vs 4066 +/- 366 pmol/l; p < 0.0005). CT scan measurements showed that the WW had significantly more visceral fat than the BW (148.5 +/- 2.0 vs 115.5 +/- 6.9 cm2; p < 0.05) but lost less weight during Dexfenfluramine treatment (-4 kg vs -9 kg). Despite this, the WW lost more visceral fat than the BW (-27.3 cm2/-18.5%; p < 0.03 vs -15.5 cm2/-13.2%; p < 0.04). In contrast the BW had a larger reduction in subcutaneous (SC) fat (-13.9% vs -1.7%; p < 0.01), with the greatest reduction in the SC gluteofemoral adipose tissue (widest hip circumference -20.8% vs -0.2%; p < 0.001) and mid-femur region (-13.1% vs -0.7%; p < 0.08).


CONCLUSIONS
Weight loss in obese black women is associated with a major reduction in SC fat mass with the most active mobilization of fat tissue occurring in the gluteofemoral area. In contrast the WW had more visceral fat that was more readily mobilized. The difference in adipose tissue distribution and pattern of mobilization was associated with lower plasma insulin, C-peptide and triglyceride concentrations in the BW despite increased FFA and glucose levels. These data suggest that plasma insulin concentrations are important in regulating differences in regional adipose tissue metabolism as well as the serum lipid profile.
van der Merwe
M T
MT
Carbohydrate and Lipid Metabolism Research Group, Johannesburg Hospital, South Africa.
Wing
J R
JR
Celgow
L H
LH
Gray
I P
IP
Lönn
L
L
Joffe
B I
BI
Lönnroth
P N
PN
D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D001741:Black or African American; D000886:Anthropometry; D001067:Appetite Depressants / Q000494:pharmacology* / Q000627:therapeutic use; D044383:Black People; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood; D002784:Cholesterol / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005277:Fenfluramine / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D007328:Insulin / Q000097:blood; D007773:Lactates / Q000097:blood; D009765:Obesity / Q000453:epidemiology / Q000208:ethnology* / Q000378:metabolism*; D012885:Skinfold Thickness; D013019:South Africa / Q000453:epidemiology / Q000208:ethnology; D014057:Tomography, X-Ray Computed; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss / Q000187:drug effects* / Q000502:physiology; D044465:White People
D001067:Appetite Depressants; D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007773:Lactates; D014280:Triglycerides; D005277:Fenfluramine; D002784:Cholesterol