Study of the mechanisms underlying increased glucose absorption in Smilax china L. leaf extract-treated HepG2 cells.
10.4163/jnh.2014.47.3.167
- Author:
Yun Hwan KANG
1
;
Dae Jung KIM
;
Kyoung Kon KIM
;
Sung Mee LEE
;
Myeon CHOE
Author Information
1. Well-being Bioproducts RIC, Kangwon National University, Chuncheon 200-701, Korea. mchoe@kangwon.ac.kr
- Publication Type:Original Article
- Keywords:
Smilax china. L;
anti-diabetic activity;
glucose uptake;
glucose transporter;
glucokinase
- MeSH:
Absorption*;
alpha-Glucosidases;
Blotting, Western;
China*;
Glucokinase;
Glucose Transport Proteins, Facilitative;
Glucose*;
Hep G2 Cells*;
Hepatocyte Nuclear Factor 1-alpha;
Smilax*;
Transcription Factors
- From:Journal of Nutrition and Health
2014;47(3):167-175
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: Previous studies have shown that treatment with Smilax china L. leaf extract (SCLE) produces antidiabetic effects due to alpha-glucosidase inhibition. In this study, we examined the mechanism underlying these antidiabetic effects by examining glucose uptake in HepG2 cells cultured with SCLE. METHODS: Glucose uptake and glucokinase activity were examined using an assay kit. Expression of glucose transporter (GLUT)-2, GLUT-4, and HNF-1alpha was measured by RT-PCR or western blot. RESULTS: Treatment with SCLE resulted in enhanced glucose uptake in HepG2 cells, and this effect was especially pronounced when cells were cultured in an insulin-free medium. SCLE induced an increase in expression of GLUT-2 but not GLUT-4. The increase in the levels of HNF-1alpha, a GLUT-2 transcription factor, in total protein extract and nuclear fraction suggest that the effects of SCLE may occur at the level of GLUT-2 transcription. In addition, by measuring the change in glucokinase activity following SCLE treatment, we confirmed that SCLE stimulates glucose utilization by direct activation of this enzyme. CONCLUSION: These results demonstrate that the potential antidiabetic activity of SCLE is due at least in part to stimulation of glucose uptake and an increase in glucokinase activity, and that SCLE-stimulated glucose uptake is mediated through enhancement of GLUT-2 expression by inducing expression of its transcription factor, HNF-1alpha.
