Epac2 activation mediates glucagon-induced glucogenesis in primary rat hepatocytes.
J Diabetes Investig
; 15(4): 429-436, 2024 Apr.
Article
em En
| MEDLINE
| ID: mdl-38243676
ABSTRACT
AIMS/INTRODUCTION:
Glucagon plays an essential role in hepatic glucogenesis by enhancing glycogen breakdown, inducing gluconeogenesis, and suppressing glycogenesis. Moreover, glucagon increases cyclic adenosine monophosphate (cAMP) levels, thereby activating protein kinase A (PKA) and cAMP guanine nucleotide exchange factor (also known as Epac). Although the function of PKA in the liver has been studied extensively, the function of hepatic Epac is poorly understood. The aim of this study was to elucidate the role of Epac in mediating the action of glucagon on the hepatocytes. MATERIALS ANDMETHODS:
Epac mRNA and protein expression, localization, and activity in the hepatocytes were analyzed by reverse transcription polymerase chain reaction, western blotting, immunofluorescence staining, and Rap1 activity assay, respectively. Additionally, we investigated the effects of an Epac-specific activator, 8-CPT, and an Epac-specific inhibitor, ESI-05, on glycogen metabolism in isolated rat hepatocytes. Further mechanisms of glycogen metabolism were evaluated by examining glucokinase (GK) translocation and mRNA expression of gluconeogenic enzymes.RESULTS:
Epac2, but not Epac1, was predominantly expressed in the liver. Moreover, 8-CPT inhibited glycogen accumulation and GK translocation and enhanced the mRNA expression of gluconeogenic enzymes. ESI-05 failed to reverse glucagon-induced suppression of glycogen storage and partially inhibited glucagon-induced GK translocation and the mRNA expression of gluconeogenic enzymes.CONCLUSIONS:
Epac signaling plays a role in mediating the glucogenic action of glucagon in the hepatocytes.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Sulfonas
/
Derivados de Benzeno
/
Glucagon
/
Hepatócitos
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article