Epinephrine mediates facultative carbohydrate-induced thermogenesis in human skeletal muscle

A Astrup, L Simonsen, J Bulow… - American Journal …, 1989 - journals.physiology.org
A Astrup, L Simonsen, J Bulow, J Madsen, NJ Christensen
American Journal of Physiology-Endocrinology and Metabolism, 1989journals.physiology.org
The thermic effect of carbohydrate has a component mediated by the sympathoadrenal
system but of unknown anatomical localization. We have studied the contribution of skeletal
muscle to the thermic effect of a carbohydrate-rich natural meal (115 g of carbohydrate,
approximately 80% of energy) by means of the forearm technique on two occasions, with
and without intravenous beta-blockade with propranolol. The meal-induced thermogenesis
was reduced from 9.6 to 7.1% by beta-blockade (P less than 0.04), the major difference was …
The thermic effect of carbohydrate has a component mediated by the sympathoadrenal system but of unknown anatomical localization. We have studied the contribution of skeletal muscle to the thermic effect of a carbohydrate-rich natural meal (115 g of carbohydrate, approximately 80% of energy) by means of the forearm technique on two occasions, with and without intravenous beta-blockade with propranolol. The meal-induced thermogenesis was reduced from 9.6 to 7.1% by beta-blockade (P less than 0.04), the major difference was found 90 to 240 min after the meal. The postprandial increments in plasma glucose and lactate did not change by beta-blockade, but there was a trend toward a decreased insulin response (P = 0.06). The carbohydrate-induced increase in forearm oxygen consumption was reduced by 23% after beta-blockade (P less than 0.05), the entire difference being present 90-180 min postprandially and coinciding with the peak in arterial epinephrine. The present study provides evidence of a facultative thermogenic component in skeletal muscle, mediated by epinephrine via beta 2-adrenoreceptors. However, it also points to a nonmuscle component mediated through beta 1-adrenoceptors by norepinephrine released from the sympathetic nervous system. Consequently, the sympathoadrenal system seems to play a physiological role in the daily energy balance.
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