Insulin attenuates leptin-induced STAT3 tyrosine-phosphorylation in a hepatoma cell line

Autor: Naruhiro Fujita, Katuya Ohshima, Yoshihiko Yamaguchi, Hironori Yamasaki, Ryoko Takahashi, Atsushi Kita, Shigeo Uotani, Mikako Degawa-Yamauchi, Hironaga Kuwahara, Hiroyuki Sakamaki, Takahiro Abe, Katsumi Eguchi
Rok vydání: 2003
Předmět:
Leptin
STAT3 Transcription Factor
medicine.medical_specialty
Carcinoma
Hepatocellular
DNA
Complementary
Time Factors
medicine.medical_treatment
Receptors
Cell Surface
Biology
Biochemistry
Mice
chemistry.chemical_compound
Endocrinology
Cell Line
Tumor
Proto-Oncogene Proteins
Internal medicine
Insulin receptor substrate
Okadaic Acid
medicine
Hyperinsulinemia
Animals
Humans
Insulin
Phosphorylation
Molecular Biology
Leptin receptor
Dose-Response Relationship
Drug
Liver Neoplasms
digestive
oral
and skin physiology
Tyrosine phosphorylation
Janus Kinase 2
Protein-Tyrosine Kinases
medicine.disease
Receptor
Insulin
DNA-Binding Proteins
chemistry
Trans-Activators
Receptors
Leptin
Tyrosine
Protein Tyrosine Phosphatases
Tyrosine kinase
hormones
hormone substitutes
and hormone antagonists
Protein Binding
Zdroj: Molecular and Cellular Endocrinology. 205:115-120
ISSN: 0303-7207
DOI: 10.1016/s0303-7207(03)00180-1
Popis: Leptin, the 16 kDa protein product of the ob gene, is secreted by adipocytes. The long form leptin receptor (ObRb) is expressed at high levels in the hypothalamus, and regulates appetite and energy expenditure. The fact that serum concentration of leptin is correlated with body mass index (BMI) suggests reduced sensitivity to leptin. Even though hyperinsulinemia and hyperleptinemia could coexist in obese humans, little is known about the interaction of insulin and leptin. In this study, we examined the effect of insulin on leptin signaling using Huh 7 cells transiently transfected with ObRb cDNA. Insulin inhibits leptin-induced STAT3 phosphorylation in a time- and dose-dependent manner without affecting Janus tyrosine kinases (JAKs) JAK2 phosphorylation. Okadaic acid prevents the inhibitory effect of insulin on leptin-induced STAT3 activation.
Databáze: OpenAIRE
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