PubMed · 9887590
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D F Roberts, G Hauser. 1998. Reflection on body composition studies.. https://pubmed.ncbi.nlm.nih.gov/9887590/
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To test the hypothesis that estrogens alter insulin action, we evaluated the effects of intravenous conjugated estrogens (CE) on insulin-stimulated steady-state glucose infusion rate (SSGIR) and suppression of plasma glycerol in postmenopausal women (mean +/- SD; 56 +/- 4 yr; n = 12) not using hormone replacement. SSGIR and glycerol were measured during a two-stage (8 and 40 mU. m-2. min-1) hyperinsulinemic euglycemic clamp on 2 days, with or without a 2.5-mg intravenous CE bolus. Serum estradiol concentrations were increased approximately 200% on the estrogen (EST) compared with the control (CON) days. Serum insulin was reduced (P < 0.01) during stage 2 of the clamp for EST (63.3 +/- 12.8 micro U/ml) vs. CON (78.2 +/- 15.8 micro U/ml). Mean SSGIR and plasma glycerol did not differ between CON and EST days. With adjustment for differences in insulin concentration between conditions, stage 2 glucose disposals were significantly higher (8.63 vs. 7.20 mg. kg-1. min-1) and plasma glycerol concentrations were significantly lower (29.4 vs. 35.0 micro mol/l) for EST vs. CON. Our findings suggest that acute CE administration increases insulin clearance and action in postmenopausal women.
Nutritional status should be assessed at regular intervals as part of management of human immunodeficiency virus (HIV) infection. The simplest approach to assessment is serial weight measurement. A comprehensive nutritional assessment includes (1) anthropometric measurements of body composition; (2) biochemical measurements of serum protein, micronutrients, and metabolic parameters; (3) clinical assessment of altered nutritional requirements and social or psychological issues that may preclude adequate intake; and (4) measurement of dietary intake. Techniques for measuring body composition of fat and lean body mass include anthropometry and bioelectric impedance analysis. Other techniques, including dual X-ray absorptiometry (DXA), hydrodensitometry, total body potassium measurement, and cross-sectional computed tomography or magnetic resonance imaging are available in research centers. Anthropometry, including waist-hip ratios, regional DXA, and cross-sectional imaging, is best for detecting morphologic changes associated with fat redistribution syndrome. Nutritional assessment and intervention in children with HIV can help to prevent stunted growth and development.
Maintenance of reduced or elevated body weight results in respective decreases or increases in energy expended in physical activity, defined as 24-h energy expenditure excluding resting energy expenditure and the thermic effect of feeding, beyond those attributable to weight change. We examined skeletal muscle work efficiency by graded cycle ergometry and, in some subjects, rates of gastrocnemius muscle ATP flux during exercise by magnetic resonance spectroscopy (MRS), in 30 subjects (15 males, 15 females) at initial weight and 10% below initial weight and in 8 subjects (7 males, 1 female) at initial weight and 10% above initial weight to determine whether changes in skeletal muscle work efficiency at altered body weight were correlated with changes in the energy expended in physical activity. At reduced weight, muscle work efficiency was increased in both cycle ergometry [mean (SD) change = +26.5 (26.7)%, P < 0.001] and MRS [ATP flux change = -15.2 (23.2)%, P = 0.044] studies. Weight gain resulted in decreased muscle work efficiency by ergometry [mean (SD) change = -17.8 (20.5)%, P = 0.043]. Changes in muscle efficiency at altered body weight accounted for 35% of the change in daily energy expended in physical activity.