Underfeeding and the physiological responses to infused epinephrine in lean women.

Undernutrition leads to a reduction in sympathetic nervous system activity, but it is not established whether whole body responsiveness to catecholamines is also affected. The physiological responses to a 30-min infusion of epinephrine at 25 ng.kg-1.min-1 were studied in seven healthy, lean female subjects who had reduced their daily food intake to 60 kJ/kg ideal body weight for 7 days. Underfeeding led to greater epinephrine-induced increases in blood glycerol [peak increment 0.14 +/- 0.02 (SE) vs. 0.08 +/- 0.01 mmol/l, P less than 0.05] and beta-hydroxybutyrate concentrations (mean increment 0.30 +/- 0.05 vs. 0.13 +/- 0.04 mmol/l, P less than 0.05, analysis of variance). Compared with the normally fed state, in the underfed state epinephrine also caused greater increases in skin temperatures measured over the abdomen (0.94 +/- 0.08 vs. 0.67 +/- 0.06 degrees C, P less than 0.05) and over the thigh (1.00 +/- 0.07 vs. 0.61 +/- 0.12 degrees C, P less than 0.01). Underfeeding did not, however, affect the chronotropic, thermogenic, or other measured responses to epinephrine. Underfeeding therefore caused an enhancement of some but not all physiological responses to infused epinephrine.