In vivo response to alpha(1)-adrenoreceptor stimulation in human white adipose tissue.
OBJECTIVE
Recent studies in rats suggest an important effect of alpha(1)-adrenoreceptor stimulation on glucose uptake in white adipocytes. It is not known if alpha(1)-adrenoreceptor stimulation elicits similar metabolic effects in humans.


METHODS
Three microdialysis catheters in abdominal subcutaneous adipose tissue were perfused with 0.00, 0.01, 0.10, 1.00, and 10.00 microM isoproterenol, phenylephrine, or phenylephrine plus 100 microM propranolol. Dialysate concentrations of ethanol, glycerol, glucose, and lactate were measured for estimating blood flow (ethanol-dilution technique), lipolysis, and glycolysis, respectively.


RESULTS
Phenylephrine, with or without propranolol, did not elicit a change in ethanol ratio. In contrast, the ethanol ratio decreased markedly with isoproterenol. Dialysate glucose concentration decreased with phenylephrine with and without propranolol and increased with isoproterenol. Phenylephrine caused a dose-dependent increase in dialysate glycerol concentration, with a maximal effect similar to that of isoproterenol. The effect was attenuated with propranolol.


CONCLUSIONS
Our findings suggest that alpha(1)-adrenoreceptor stimulation by phenylephrine increases glucose uptake and metabolism in human abdominal adipose tissue. Furthermore, phenylephrine elicits a marked increase in lipolytic activity in white adipose tissue through beta-adrenoreceptor activation.
Boschmann
Michael
M
German Institute of Human Nutrition, Potsdam, Germany. boschman@www.dife.de
Krupp
Götz
G
Luft
Friedrich C
FC
Klaus
Susanne
S
Jordan
Jens
J
D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism*; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D000328:Adult; D000431:Ethanol / Q000032:analysis; D005947:Glucose / Q000032:analysis; D005990:Glycerol / Q000032:analysis; D006019:Glycolysis; D006801:Humans; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology; D019344:Lactic Acid / Q000032:analysis; D008066:Lipolysis; D008297:Male; D017551:Microdialysis; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects* / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; D019344:Lactic Acid; D000431:Ethanol; D011433:Propranolol; D005947:Glucose; D007545:Isoproterenol; D005990:Glycerol