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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #98091
Title: MODULATION OF PORCINE ADIPOCYTE BETA-ADRENERGIC RECEPTORS BY A BETA-ADRENERGIC AGONIST

Author
item DING, SHIH-TORNG - BAYLOR COLLEGE OF MED
item MCNEEL, RONALD - BAYLOR COLLEGE OF MED
item SMITH, E - BAYLOR COLLEGE OF MED
item Mersmann, Harry

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Beta-adrenergic receptors (BAR), which are present on the surface of most types of mammalian cells, control fat cell metabolism and fat tissue growth. Pig fat-cell BAR have different behavior and functions than the BAR in other species. Because of these differences, we studied pig fat cells that were incubated with and without isoproterenol, which is a BAR agonist, ,meaning a substance that can combine with a BAR receptor and produce a biological reaction. After incubation with isoproterenol, there was a modest decrease in the number of BAR but not in transcript concentration, which is different from what has been seen in other types of mammals. The results suggested that the BAR were desensitized by incubation with isoproterenol. These study findings further investigators' understanding of fat cells in pigs, which are an animal model for the human.

Technical Abstract: Mammalian cells have mechanisms to decrease the response to beta-adrenergic agonists. Agonists are metabolized or taken up by nerve endings. The beta- adrenergic receptors (betaAR) are inactivated by phosphorylation, removed from the cells membrane, and synthesis is decreased or degradation is increased. Isolated porcine adipocytes were incubated without or with a betaAR agonist, isoproterenol (ISO). The total betaAR number, measured by ligand-binding in a crude membrane fraction, decreased approximately 24 percent after six hours of incubation without ISO. The addition of 10-5 M ISO during the incubation caused the betaAR number to decrease an additional 29 percent. The beta1AR and beta2AR transcript concentrations did not change in adipocytes incubated for 6 hours with ISO compared to cells incubated without ISO. The results suggest the betaAR were desensitized by incubation with ISO, perhaps by phosphorylation and removal lfrom the membrane, but this was not accomplished by modulation of the concentration of transcripts for beta1AR or beta2AR.