beta-Adrenergic stimulation controls the expression of a thioesterase specific for very-long-chain fatty acids in perfused hearts.
Arachidonic acid is not freely stored in the cells. A number of different pathways for the mobilization of this compound have been proposed, including a novel mechanism that involves the release of arachidonic acid from arachidonoyl-CoA by a thioesterase with substrate specificity for very-long-chain fatty acids. In rat heart, the acyl-CoA thioesterase activity can be regulated by a mechanism that involves beta-adrenoceptors. In this paper we demonstrate that beta-adrenergic agonists also regulate the acyl-CoA thioesterase mRNA levels. Isoproterenol (10(-7)M)-a concentration known to exert physiological responses-increases in a time-dependent manner the acyl-CoA thioesterase mRNA levels, an effect blocked by a specific beta-adrenoceptor antagonist. In addition, our results show that cAMP is involved in this process. The acyl-CoA thioesterase mRNA levels are also increased by fasting, but not by di(2-ethylhexyl)phthalate, a peroxisome proliferator. These results may suggest the existence of a beta-adrenoceptor-activated regulatory pathway for arachidonic acid release in cardiac tissue.
Neuman
Isabel
I
Department of Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina. ineuman@fmed.uba.ar
Maloberti
Paula
P
Lisdero
Constanza
C
Colonna
Cecilia
C
Peralta
Jorge
J
José
Juan Poderoso
JP
Podestá
Ernesto J
EJ
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D003609:Dactinomycin / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism*; D006321:Heart / Q000502:physiology*; D007150:Immunohistochemistry; D007545:Isoproterenol / Q000494:pharmacology; D010477:Perfusion; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000096:biosynthesis*; D013997:Time Factors
D000318:Adrenergic beta-Agonists; D005227:Fatty Acids; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; D011994:Recombinant Proteins; D003609:Dactinomycin; D016718:Arachidonic Acid; D013869:Thiolester Hydrolases; D007545:Isoproterenol