Regional lipolytic responses to isoproterenol in women.
We previously found that epinephrine, a mixed beta- and alpha-adrenoreceptor agonist, stimulates systemic and nonsplanchnic upper body free fatty acid (FFA) release but not lower body FFA release in healthy nonobese women. To evaluate the role of beta-adrenergic-mediated effects on this regional difference in lipolysis, we measured systemic, leg, and splanchnic FFA kinetics ([3H]palmitate) in seven healthy nonobese women before and during an intravenous isoproterenol infusion. Isoproterenol increased systemic palmitate flux (87 +/- 12 vs. 100 +/- 10 mumol/min, P < 0.05) but failed to affect leg [10.8 +/- 1.2 vs. 11.4 +/- 2.3 mumol/min, P = not significant (NS)] or splanchnic (10.8 +/- 3.2 vs. 10.0 +/- 1.8 mumol/min, P = NS) palmitate release. Upper body nonsplanchnic palmitate release increased from 56 +/- 14 to 71 +/- 10 mumol/min. Systemic O2 consumption increased (227 +/- 11 to 241 +/- 10 ml/min, P = 0.006) during isoproterenol infusion, as did leg (318 +/- 42 vs. 404 +/- 53 ml/min, P < 0.01) and splanchnic (827 +/- 104 vs. 970 +/- 108 ml/min, P < 0.05) plasma flow. These results suggest that lower body adipose tissue lipolysis in women is less sensitive or responsive than nonsplanchnic upper body adipose tissue to beta-adrenergic stimulation and that regional differences in alpha 2-adrenergic-receptor responses were not responsible for the similar regional differences we observed previously with epinephrine.
Guo
Z
Z
Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA.
Johnson
C M
CM
Jensen
M D
MD
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium; D004837:Epinephrine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005934:Glucagon / Q000097:blood; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology*; D007866:Leg / Q000098:blood supply; D008066:Lipolysis / Q000187:drug effects*; D019308:Palmitic Acid / Q000097:blood*; D017697:Premenopause; D013152:Splanchnic Circulation; D013997:Time Factors
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D019382:Human Growth Hormone; D019308:Palmitic Acid; D005934:Glucagon; D003903:Deuterium; D007545:Isoproterenol; D004837:Epinephrine