Decreased hepatic response to glucagon, adrenergic agonists, and cAMP in glycogenolysis, gluconeogenesis, and glycolysis in tumor-bearing rats.
J Cell Biochem
; 119(9): 7300-7309, 2018 09.
Article
em En
| MEDLINE
| ID: mdl-29761924
ABSTRACT
The response to glucagon and adrenaline in cancer cachexia is poorly known. The aim of this study was to investigate the response to glucagon, adrenergic agonists (α and ß) and cyclic adenosine monophosphate (cAMP) on glycogenolysis, gluconeogenesis, and glycolysis in liver perfusion of Walker-256 tumor-bearing rats with advanced cachexia. Liver ATP content was also investigated. Rats without tumor (healthy) were used as controls. Agonists α (phenylephrine) and ß (isoproterenol) adrenergic, instead of adrenaline, and cAMP, the second messenger of glucagon and isoproterenol, were used in an attempt to identify mechanisms involved in the responses. Glucagon (1 nM) stimulated glycogenolysis and gluconeogenesis and inhibited glycolysis in the liver of healthy and tumor-bearing rats, but their effects were lower in tumor-bearing rats. Isoproterenol (20 µM) stimulated glycogenolysis, gluconeogenesis, and glycolysis in healthy rats and had virtually no effect in tumor-bearing rats. cAMP (9 µM) also stimulated glycogenolysis and gluconeogenesis and inhibited glycolysis in healthy rats but had practically no effect in tumor-bearing rats. Phenylephrine (2 µM) stimulated glycogenolysis and gluconeogenesis and inhibited glycolysis and these effects were also lower in tumor-bearing rats than in healthy. Liver ATP content was lower in tumor-bearing rats. In conclusion, tumor-bearing rats with advanced cachexia showed a decreased hepatic response to glucagon, adrenergic agonists (α and ß), and cAMP in glycogenolysis, gluconeogenesis, and glycolysis, which may be due to a reduced rate of regulatory enzyme phosphorylation caused by the low ATP levels in the liver.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Glucagon
/
AMP Cíclico
/
Agonistas Adrenérgicos
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Glicogenólise
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Gluconeogênese
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Glicólise
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Fígado
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Neoplasias
Tipo de estudo:
Etiology_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Cell Biochem
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Brasil