title: Modulation of beta-adrenergic receptor-stimulated lipolysis in the heart by prostaglandins.
abstract: The purpose of the present study was to investigate the contribution of prostaglandins to lipolysis elicited by beta-adrenergic receptor activation in the heart. We have studied the effect of prostaglandin E2 (PGE2), prostaglandin I2 (PGI2), and their precursor arachidonic acid (AA) in the presence and absence of a cyclooxygenase inhibitor, sodium meclofenamate, on glycerol output elicited by stimulation of beta-adrenergic receptors in the isolated rabbit heart with isoproterenol (ISOP). Bolus injections of ISOP (475 pmol) produced a constant increase in glycerol and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) output. Infusion of sodium meclofenamate (16 microM) reduced basal and attenuated ISOP-induced 6-keto-PGF1 alpha output and enhanced glycerol output. During inhibition of endogenous prostaglandin synthesis with meclofenamate, infusion of PGI2 or PGE2 (0.1-1 microM) inhibited ISOP-induced glycerol output. Infusion of AA (0.1-1 microM) increased 6-keto-PGF1 alpha and reduced glycerol output. Infusion of sodium meclofenamate abolished the effect of AA to increase 6-keto-PGF1 alpha and to decrease glycerol output. These data suggest that prostaglandins synthesized in the heart act as an inhibitory modulator of beta-adrenergic receptor-stimulated cardiac lipolysis.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Tennessee, Memphis 38163, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Ruan
authors.forename: H
authors.initials: H
authors.lastname: Kan
authors.forename: C
authors.initials: C
authors.lastname: Cano
authors.forename: K U
authors.initials: KU
authors.lastname: Malik
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D015232:Dinoprostone / Q000494:pharmacology*; D011464:Epoprostenol / Q000494:pharmacology*; D008066:Lipolysis / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010120:Oxytocics / Q000494:pharmacology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
chemical_list: D010120:Oxytocics; D010975:Platelet Aggregation Inhibitors; D011943:Receptors, Adrenergic, beta; D016718:Arachidonic Acid; D011464:Epoprostenol; D015232:Dinoprostone