title: Adrenergic control of lipolysis in women compared with men.
abstract: Data suggest women are more sensitive to the lipolytic action of epinephrine compared with men while maintaining similar glucoregulatory effects (Horton et al. J Appl Physiol 107: 200-210, 2009). This study aimed to determine the specific adrenergic receptor(s) that may mediate these sex differences. Lean women (n = 14) and men (n = 16) were studied on 4 nonconsecutive days during the following treatment infusions: saline (S: control), epinephrine [E: mixed β-adrenergic (lipolytic) and α2-adrenergic (antilipolytic) stimulation], epinephrine + phentolamine (E + P: mixed β-adrenergic stimulation only), and terbutaline (T: selective β2-adrenergic stimulation). Tracer infusions of glycerol, palmitate, and glucose were administered to determine systemic lipolysis, free fatty acid (FFA) release, and glucose turnover, respectively. Following basal measurements, substrate and hormone concentrations were measured in all subjects over 90 min of treatment and tracer infusion. Women had greater increases in glycerol and FFA concentrations with all three hormone infusions compared with men (P < 0.01). Glycerol and palmitate rate of appearance (Ra) and rate of disappearance (Rd) per kilogram body weight were greater with E infusion in women compared with men (P < 0.05), whereas no sex differences were observed with other treatments. Glucose concentration and kinetics were not different between sexes with any infusion. In conclusion, these data support the hypothesis that the greater rate of lipolysis in women with infusion of E was likely due to lesser α2 antilipolytic activation. These findings may help explain why women have greater lipolysis and fat oxidation during exercise, a time when epinephrine concentration is elevated.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado; The Obesity Treatment Foundation, Aurora, Colorado stacy@asbp.org.
authors.forename: Stacy L
authors.initials: SL
authors.lastname: Schmidt
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Denver Health Medical Center, Denver, Colorado;
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Bessesen
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
authors.forename: Sarah
authors.initials: S
authors.lastname: Stotz
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; and.
authors.forename: Frederick F
authors.initials: FF
authors.lastname: Peelor
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; and.
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Miller
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
authors.forename: Tracy J
authors.initials: TJ
authors.lastname: Horton
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008066:Lipolysis / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D019308:Palmitic Acid / Q000097:blood; D010646:Phentolamine / Q000494:pharmacology*; D012727:Sex Characteristics; D013726:Terbutaline / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D019308:Palmitic Acid; D013726:Terbutaline; D009638:Norepinephrine; D004837:Epinephrine; D010646:Phentolamine
keywords: adrenergic receptors; epinephrine; glucose kinetics; lipolysis; sex differences