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PubMed · 8381742

Hepatocyte homologous beta 2-adrenergic desensitization is associated with a decrease in number of plasma membrane beta 2-adrenoceptors.

O Medina-Martínez·J A García-Sáinz
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Abstract

Preincubation of rat hepatocytes with isoproterenol induces homologous beta-adrenergic desensitization evidenced both in whole cells (cyclic AMP accumulation) and membranes (adenylyl cyclase activity). This desensitization is associated with and quantitatively similar to a loss of beta 2-adrenoceptors from the plasma membrane. Desensitization did not alter the affinities of isoproterenol for the [125I]iodocyanopindolol binding sites nor reduce the ability of guanine nucleotides to modulate agonist affinity, i.e., the receptors that remain in the surface of plasma membrane after desensitization (approximately 50%) retain their functional integrity. When membranes from isoproterenol-desensitized hepatocytes were treated with alkaline phosphatase, no attenuation of the desensitization was observed. Cholera toxin-catalyzed ADP-ribosylation was not decreased but rather slightly increased in membranes from desensitized cells as compared to the controls. Our data indicate that in hepatocytes, a loss of beta 2-adrenoceptors from the plasma membrane is closely associated to the homologous desensitization induced by isoproterenol.

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Adenosine Diphosphate RiboseAdenylyl CyclasesAlkaline PhosphataseAnimalsAutoradiographyBinding, CompetitiveCell MembraneCholera ToxinConcanavalin ACyclic AMPFemaleHypothyroidismIn Vitro TechniquesIodocyanopindololIsoproterenolKineticsLiverPindololRatsRats, WistarReceptors, Adrenergic, betaJournal ArticleResearch Support, Non-U.S. Gov't

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O Medina-Martínez, J A García-Sáinz. 1993-01-15. Hepatocyte homologous beta 2-adrenergic desensitization is associated with a decrease in number of plasma membrane beta 2-adrenoceptors.. https://doi.org/10.1016/0922-4106(93)90020-a

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