RESUMEN
OBJECTIVE: To investigate the effect of weight reduction induced by gastric bypass operation (GBO), on the peripheral resistance to insulin in extremely obese subjects. DESIGN: A three-stage euglycemic clamp was applied to assess the metabolic clearance rate of glucose (g-MCR) in lean controls and in obese subjects, prior to and 6-12 months post operation. SUBJECTS: Six obese subjects (four obese normoglycemics-ON and two obese non-insulin dependent diabetics-OD) before and after GBO and six healthy, lean controls (LC) were compared. MAIN OUTCOME MEASURES: Body mass index after GBO, metabolic clearance rate of glucose under increasing insulin concentrations. RESULTS: GBO resulted in a significant change in body mass index from a pre-operation value (mean +/- s.d.) of 45.0 +/- 8.5 to 30.4 +/- 5.9 kg m-2 and remained significantly greater than controls (23.3 +/- 2.3 kg m-2). Glucose MCR increased from a mean baseline value of 3.0 +/- 1.6 to 6.7 +/- 3.9 ml kg-1 min-1 at post GBO (P) (P < 0.02). Similar effects were obtained under the two higher insulin concentration. CONCLUSIONS: GBO resulted in a massive reduction in BMI, that still remained above normal controls. This could explain the effect of weight reduction to decrease, but not completely reverse, peripheral resistance to insulin associated with obesity.
Asunto(s)
Derivación Gástrica/normas , Glucosa/metabolismo , Obesidad Mórbida/metabolismo , Obesidad Mórbida/cirugía , Pérdida de Peso/fisiología , Adolescente , Adulto , Índice de Masa Corporal , Diabetes Mellitus/metabolismo , Diabetes Mellitus/fisiopatología , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Humanos , Insulina/análisis , Resistencia a la Insulina/fisiología , Masculino , Tasa de Depuración Metabólica , Obesidad , Obesidad Mórbida/fisiopatologíaRESUMEN
Sixteen male subjects [18-21 years, maximal oxygen consumption (VO2max) = 59.2 ml.kg-1.min-1 +/- SEM 5.6] participated in a study to evaluate the effect of prolonged, complete food deprivation combined with physical effort, on plasma lipoprotein concentrations. The subjects were deprived of food for 81 h but were supplied with water: they walked for 10 h a day at 40% of VO2max, covering a total of 105 km. During this period the subjects' average mass decreased significantly (P less than 0.05) reflecting a marked catabolic process. Plasma concentration of low density lipoprotein-cholesterol [( LDL-C]) and triglycerides were significantly lower (P less than 0.05) and total cholesterol, high-density lipoprotein-cholesterol [( HDL-C]), and free fatty acid levels were significantly higher (P less than 0.05) at the end of the experimental period compared to the start. The ratio between plasma [HDL-C] to plasma [LDL-C] increased from 0.51 to 0.89 at the end of the exercise period, reflecting a marked anti-atherogenic effect. All changes were transient and reversible within 12 days of recovery.