beta-Adrenoceptor activity and resting energy metabolism in weight losing cancer patients

This study was aimed at comparing the blocking of beta-adrenoceptor activit y to changes in the resting energy metabolism of 10 cancer patients with pr ogressive weight loss due to solid malignant tumours. Resting energy expend iture (REE) as well as whole body carbohydrate and fat oxidation were inves tigated and related to plasma substrate levels (glucose, glycerol, free fat ty acids (FFA)) before and after 5 days of oral administration of specific beta 1 receptor blocker (atenolol, 50 mg/day) and non-specific beta 1.beta 2- adrenoceptor (propranolol. 80 mg/day) blockade. The administration order of the drugs was random, and a 3-day washout period was used in all indivi duals between the provision of the first and the second drug in order to mi nimise the risk of carry-over effects. Resting measurements in the morning after an overnight fast were performed by indirect calorimetry. Atenolol tr eatment reduced REE by 77 +/- 14 kcal:day and propranolol by 48 +/- 13 kcal /day. respectively (P < 0.05 versus pretreatment values). Whole body oxygen uptake and carbon dioxide production were decreased similarly by both aten olol and propranolol treatment (P < 0.05). Carbohydrate oxidation was incre ased by atenolol and decreased by propranolol, whilst fat oxidation was dec reased by atenolol and unchanged by propranolol. The decrease in REE, accou nting for the decline in heart rate, was significantly mort pronounced foll owing treatment with propranolol compared with atenolol (P < 0.05). Atenolo l and propranolol had no effect on blood glucose, plasma glycerol and FFA. We conclude that wastage in cancer patients is in part explained by increas ed beta(1) and beta(2)-adrenoceptor activity, in part secondary to elevated cardiovascular activity as a result of anaemia, loss of cardiac contractil e capacity and altered host metabolism. (C) 2000 Elsevier Science Ltd. All rights reserved.