Reduction of Plasma Catecholamines in Humans during Clinically Controlled Severe Underfeeding

Background. Sympathetic hyperactivity is one factor for alterations encountered in the plurimetabolic syndrome, a cluster of metabolic abnormalities including obesity, hyperlipidemia, sometimes hyperglycaemia, and hypertonia. It was interesting to know if prolonged severe underfeeding (230 kcal/day) leads to decreases in catecholamines in those patients. Methods. The plasma concentrations of catecholamines in patients (n = 16) suffering from plurimetabolic syndrome were studied before and during a 16-day period of medically controlled severe underfeeding (230 kcal/day) at rest and in response to exercise. Results. During the period of underfeeding, mean norepinephrine concentrations decreased at rest from 1.45 to 0.96 nmol/liter, and in response to exercise, from 6.1 to 3.2 nmol/liter. Epinephrine concentrations decreased from 0.15 to 0.1 nmol/liter and from 0.26 to 0.17 nmol/liter, respectively. A significant decrease in catecholamine concentrations was observed only after 16 days of underfeeding. Conclusions. Clinically controlled underfeeding of patients with plurimetabolic syndrome may result in beneficial clinical and biochemical effects. The findings indicate that relatively long periods of underfeeding induce decreases in plasma catecholamine concentrations. Nevertheless, most of the fall in mean values in norepinephrine and also of the fall in blood pressure values occurred by Day 2. From those tendencies and from the significant changes in both parameters at Day 16 of severe underfeeding one could conclude that altered sympathetic nervous system activity could contribute to the fall in blood pressure.