No abstract

Insulin and (-)-epigallocatechin gallate (EGCG) are reported to regulate obesity and fat accumulation, respectively. This study investigated the pathways involved in EGCG modulation of insulin-stimulated glucose uptake in 3T3-L1 and C3H10T1/2 adipocytes. EGCG inhibited insulin stimulation of adipocyte glucose uptake in a dose- and time-dependent manner. The concentration of EGCG that decreased insulin-stimulated glucose uptake by 50-60% was approximately 5-10 µM for a period of 2 h. At 10 µM, EGCG and gallic acid were more effective than (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin 3-gallate. We identified the EGCG receptor [also known as the 67-kDa laminin receptor (67LR)] in fat cells and extended the findings for this study to clarify whether EGCG-induced changes in insulin-stimulated glucose uptake in adipocytes could be mediated through the 67LR. Pretreatment of adipocytes with a 67LR antibody, but not normal rabbit immunoglobulin, prevented the effects of EGCG on insulin-increased glucose uptake. This suggests that the 67LR mediates the effect of EGCG on insulin-stimulated glucose uptake in adipocytes. Moreover, pretreatment with an AMP-activated protein kinase (AMPK) inhibitor, such as compound C, but not with a glutathione (GSH) activator, such as N-acetyl-L-cysteine (NAC), blocked the antiinsulin effect of EGCG on adipocyte glucose uptake. These data suggest that EGCG exerts its anti-insulin action on adipocyte glucose uptake via the AMPK, but not the GSH, pathway. The results of this study possibly support that EGCG mediates fat content.

No abstract

Green tea catechins, especially (-)-epigallocatechin-3-gallate (EGCG), are known to regulate obesity and fat accumulation. We performed a kinetic analysis in a cell-free system to determine the mode of inhibition of glycerol-3-phosphate dehydrogenase (GPDH; EC 1.1.1.8) by EGCG. GPDH catalyzes the beta-nicotinamide adenine dinucleotide (NADH)-dependent reduction of dihydroxyacetone phosphate (DHAP) to yield glycerol-3-phosphate, which serves as one of the major precursors of triacylglycerols. We found that EGCG dose-dependently inhibited GPDH activity at a concentration of approximately 20 muM for 50 % inhibition. The IC (50) values of other green tea catechins, such as (-)-epicatechin, (-)-epicatechin-3-gallate, and (-)-epigallocatechin, were all above 100 microM. This suggests a catechin type-dependent effect. Based on double-reciprocal plots of the kinetic data, EGCG was a noncompetitive inhibitor of the GPDH substrates, NADH and DHAP, with respective inhibition constants (Ki) of 18 and 31 microM. Results of this study possibly support previous studies that EGCG mediates fat content.

This paper introduces the superjet-midi (SJM) method, which has been developed to improve the efficiency of jet grouting. The diameters of soilcrete columns constructed with the new method are relatively large (2 . 4-3 . 5 m). Advantages and limitations of the SJM method are summarised. To examine the quality of construction, cylindrical SJM specimens were recovered at the site, and field and laboratory tests were conducted. It is found that the jet-sounding technique is a simple and economical measure to estimate the effective diameter of soilcrete columns. The rock quality designation of specimens varies from 79% to 97%, which indicates that the quality of the soilcrete is good. The uniaxial compressive strength q u of jumbo-jet special grout and SJM specimens are similar. The modulus of elasticity E t50 varies from 350 to 1990 MN/ m 2 . These data are in good agreement with the range E 50 100q u -300q u suggested by the JSG Association. Axial failure strains of SJM soilcrete are relatively close to the failure strains for concrete rather than those for soil.Cet exposé présente la méthode superjet-midi (SJM) qui a été développée afin d'améliorer l'efficacité de l'injection de ciment. Les diamètres des colonnes de sol bétonné construites grâce à la nouvelle méthode sont relativement importants (2 . 4-3 . 5 m). Nous résumons les avantages et les limitations de la méthode SJM. Pour examiner la qualité de la construction, des spécimens SJM cylindriques ont été récupérés sur le site et des essais sur le terrain et en laboratoire ont été menés. Nous avons trouvé que la technique de sondage sous injection est un moyen simple et économique pour évaluer le diamètre effectif des colonnes de sol bétonné. La désignation de qualité rocheuse des spécimens varie de 79% à 97%, ce qui indique que la qualité du sol bétonné est bonne. Les forces compressives uniaxiales qu des spécimens JSG et SJM sont similaires. Le module d'élasticité E t50 varie de 350 à 1990 MN/m2. Ces données concordent avec la gamme E50 100qu -300qu suggérée par l'Association JSG. Les déformations de rupture axiale du sol bétonné SJM sont relativement plus proches des déformations de rupture du béton que de celles du sol.