Green tea extract improves running endurance in mice by stimulating lipid utilization during exercise

Abstract

A series of polyphenols known as catechins are abundant in green tea, which is consumed mainly in Asian countries. The effects of catechin-rich green tea extract (GTE) on running endurance and energy metabolism during exercise in BALB/c mice were investigated. Mice were divided into four groups: nonexercise control, exercise control (Ex-cont), exercise+0.2% GTE, and exercise+0.5% GTE groups. Treadmill running time to exhaustion, plasma biochemical parameters, skeletal muscle glycogen content, beta-oxidation activity, and malonyl-CoA content immediately after exercise were measured at 8-10 wk after the initiation of the experiment. Oxygen consumption and respiratory exchange ratio were measured using indirect calorimetry. Running times to exhaustion in mice fed 0.5% GTE were 30% higher than in Ex-cont mice and were accompanied by a lower respiratory exchange ratio, higher muscle beta-oxidation activity, and lower malonyl-CoA content. In addition, muscle glycogen content was high in the GTE group compared with the Ex-cont group. Plasma lactate concentrations in mice fed GTE were significantly lower after exercise, concomitant with an increase in free fatty acid concentrations. Catechins, which are the main constituents of GTE, did not show significant effects on peroxisome proliferator-activated receptor-alpha or delta-dependent luciferase activities. These results suggest that the endurance-improving effects of GTE were mediated, at least partly, by increased metabolic capacity and utilization of fatty acid as a source of energy in skeletal muscle during exercise.

The Anti-fatigue Effects of the Low-Molecular-Weight Fraction of Bonito Extract in Mice

“…The forced swimming model has been used to evaluate the anti-fatigue effects of various compounds, [12][13][14][15] since this apparatus works well for evaluating the endurance capacity of mice and gives a high reproducibility. 10) BE was found to prolong the swimming time in this forced swimming test, indicating that BE possesses an anti-fatigue effect (Fig.…”

“…This apparatus was used to evaluate the endurance capacity of mice that had been administered with various compounds. [12][13][14][15] Male 5-week-old CD2F-1 mice were made to swim for 20 min at a flow rate of 6 l/min twice in one week to accustom them to swimming. We selected mice suitable for evaluating endurance capacity following the method described previously.…”

A Quantitative Description of Lipid and Extracellular Matrix Proteinaceous Fibers in Hepatic Fibrosis of a Rat Model by ImageJ using Nano-Images

“…Information about the ImageJ macro language is available at rsb.info.nih.gov/ij/developer/macro/macros. html [6][7][8][9][10] …”

Novel pharmacological approaches to combat obesity and insulin resistance: targeting skeletal muscle with ‘exercise mimetics’

“…Murase et al [89] have shown in mice that 8 to 10 weeks ingestion of green tea extract, containing concentrated levels of various catechin molecules, increased endurance exercise performance when combined with exercise training. However, they did not report whether green tea extract alone enhanced endurance.…”

“…Green tea catechins can activate AMPK in non-muscle cells [90,91], suggesting a mechanism similar to other AMPK activators such as AICAR [55] and resveratrol [50]. However, Murase et al [89] suggest that the actions of green tea extract in skeletal muscle are independent of PPARα/δ signalling, which contrasts with the purported mechanism of AICAR treatment [55]. Green tea extract/catechin ingestion could therefore be part of a potential exercise mimetic strategy; however, more work is required to determine the signalling mechanisms responsible, as well as whether green tea extract/catechin can act alone or only in concert with training.…”