Two-week stimulation or blockade of the sympathetic nervous system in man: influence on body weight, body composition, and twenty four-hour energy expenditure.
Seven lean healthy young men were studied for 6 weeks during exposure to pharmacologic inhibition or stimulation of the sympathetic nervous system. For a period of 2 weeks their beta-adrenergic receptors were either blocked with propranolol hydrochloride (160 mg/d) or stimulated with terbutaline sulphate (15 mg/d). After a further 2 weeks of placebo administration (500 mg lactose/d), the subjects crossed over to the drug they had not been taking at the beginning of the experiment for another 14 days. During the last five days of each 2-week period, the subjects consumed a weight-maintaining diet, composed of 12% protein, 48% carbohydrate, and 40% fat. They consumed exactly the same menus on the same days during the subsequent study periods. Body weight and physical activity were measured every day for 6 weeks. Daily heart rate and nitrogen excretion were measured continuously for days at the end of each 2-week period, the last two days of which were spent in a respiration chamber where energy expenditure and a variety of metabolic parameters were measured. In the respiration chamber on the propranolol, placebo, and terbutaline treatments, respectively, significant differences were observed in mean daily heart rate (65 +/- 3, 75 +/- 4, and 84 +/- 4 beats/min), mean sleeping heart rate (51 +/- 2, 56 +/- 3, and 62 +/- 3 beats/min), nitrogen excretion (13.6 +/- 0.7, 12.6 +/- 0.6, and 11.9 +/- 0.6 g/d), fat oxidation (+1,045 +/- 95, +1,243 +/- 148, and +1,278 +/- 84 kcal/d) and thyroid hormones (12.0 +/- 0.7, 15.7 +/- 0.9, and 17.2 +/- 1.0 T3/T4 ratio).(ABSTRACT TRUNCATED AT 250 WORDS)
Acheson
K J
KJ
Institute of Physiology, University of Lausanne, Switzerland.
Ravussin
E
E
Schoeller
D A
DA
Christin
L
L
Bourquin
L
L
Baertschi
P
P
Danforth
E
E
Jéquier
E
E
D000328:Adult; D001794:Blood Pressure; D001823:Body Composition / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects*; D002395:Catecholamines / Q000652:urine; D002986:Clinical Trials as Topic; D004032:Diet; D004734:Energy Metabolism / Q000187:drug effects*; D006339:Heart Rate; D006801:Humans; D008297:Male; D009584:Nitrogen / Q000652:urine; D005082:Physical Exertion; D011433:Propranolol / Q000494:pharmacology*; D013726:Terbutaline / Q000494:pharmacology*; D013963:Thyroid Hormones / Q000097:blood
D002395:Catecholamines; D013963:Thyroid Hormones; D011433:Propranolol; D009584:Nitrogen; D013726:Terbutaline