Pharmacological characterization of alpha1- and beta-adrenergic synergism of 5'DII activity in rat brown adipocytes.
Arch Physiol Biochem
; 112(1): 23-30, 2006 Feb.
Article
em En
| MEDLINE
| ID: mdl-16754200
ABSTRACT
The role of adrenoceptor subtypes was studied in rat brown adipose tissue (BAT). The type II 5'-deiodinase (5'DII) was activated in response to simultaneous stimulation by beta3- and alpha1-adrenergic agonists, BRL 37344 or CGP 12177, and cirazoline, in brown adipocytes. Inhibition of the alpha1- and beta-adrenergic phenylephrine-stimulated 5'DII activity was obtained by the alpha1-adrenergic antagonists in the order of prazosin >/= wb 4101 > 5-methylurapidil. In comparison, the binding of [3H]prazosin to rat BAT plasma membranes was inhibited by alpha1-adrenergic antagonists in the order of prazosin > WB 4101 = benoxathian > 5-methylurapidil. Although the order of the alpha1-adrenergic competition seemed to be rather typical for the alpha1B-adrenergic receptors, a molecular analysis on adrenoceptor mRNAs should be made to confirm the exact alpha1-adrenergic subtypes at the level of brown adipocytes, since the possibility of a mixture of different receptor subtypes in brown fat cells and/or tissue may interact with the pharmacological characterization. Thus, specific alpha1- and beta-adrenoceptor subtypes participate in the regulation of 5'DII activity in the rat brown adipocytes, and therefore, an impaired alpha1- and beta-adrenergic co-work may be involved in a defective BAT function, e.g., in obese Zucker rats, too. An interesting possibility is that the decreased number of alpha1-adrenoceptors in the BAT of obese Zucker rats is due to the decrease in the alpha1B-adrenoceptor subtype which would further be involved especially in the regulation of BAT 5'DII activity.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tecido Adiposo Marrom
/
Receptores Adrenérgicos alfa
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Receptores Adrenérgicos beta
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Agonistas alfa-Adrenérgicos
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Agonistas Adrenérgicos beta
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Iodeto Peroxidase
Limite:
Animals
Idioma:
En
Revista:
Arch Physiol Biochem
Assunto da revista:
BIOQUIMICA
/
FISIOLOGIA
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Finlândia