Effect of β2‐adrenergic receptor polymorphisms on epinephrine and exercise‐stimulated lipolysis in humans. Issue 5 (20th May 2014)

• Record Type: Journal Article
• Authors: Du, Shichun; Joyner, Michael J.; Curry, Timothy B.; Eisenach, John H.; Johnson, Christopher P.; Schrage, William G.; Jensen, Michael D.
• Is Part Of: Physiological reports. Volume 2:Issue 5(2014:May)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2014-05-20
• Subjects: Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.12017
• Languages: English
• ISSNs: 2051-817X

Abstract

<abstract abstract-type="main" id="phy212017-abs-0001"> <title>Abstract</title> <p>The <italic>β</italic><sub>2</sub>‐adrenergic system is an important regulator of human adipose tissue lipolysis. Polymorphisms that result in amino acid substitutions in the <italic>β</italic><sub>2</sub>‐adrenergic receptor have been reported to alter lipolysis. We hypothesized that variations in the amino acid at position 16 of the <italic>β</italic><sub>2</sub>‐adrenergic receptor would result in different lipolytic responses to intravenous epinephrine and exercise. 17 volunteers homozygous for glycine at position 16 (Gly/Gly, nine female) and 16 volunteers homozygous for arginine at position 16 (Arg/Arg, eight female) of the <italic>β</italic><sub>2</sub>‐adrenergic receptor participated in this study. On one study day participants received infusions of epinephrine at submaximal (5 ng kg<sup>−1</sup> min<sup>−1</sup>) and maximal (40 ng kg<sup>−1</sup> min<sup>−1</sup>) lipolytic doses. The other study day volunteers bicycled for 90 min at 50–60% of maximum oxygen consumption (VO<sub>2</sub>max). [9, 10‐<sup>3</sup>H] Palmitate was infused both days to measure free fatty acid – palmitate kinetics. Oxygen consumption was measured using indirect calorimetry. Palmitate release rates in response to epinephrine and exercise were not different in the Gly/Gly and Arg/Arg participants. The only statistically significant difference we observed was a lesser ΔVO<sub>2</sub> in Arg/Arg volunteers in response to the submaximal epinephrine infusion. The polymorphisms resulting in Arg/Arg and Gly/Gly at position 16 of the <italic>β</italic><sub>2</sub>‐adrenergic receptor do not result in clinically meaningful differences in lipolysis responses to epinephrine or submaximal exercise.</p> </abstract>