Exercise and green tea extract stimulate fat oxidation and prevent obesity in mice.

INTRODUCTION/PURPOSE: The purpose of the present study was to explore the combined effects of dietary supplementation with green tea extract (GTE) and regular exercise on the development of obesity in high fat-fed C57BL/6J mice. METHODS: Weight and age-matched male mice were divided into 5 groups of 10 mice each. Groups were treated as follows: a low-fat diet and not exercised (LF), a high-fat diet and not exercised (HF), a high-fat diet supplemented with GTE and not exercised (GTE-HF), a high-fat diet and exercised regularly (EX-HF), or a high-fat diet supplemented with GTE and exercised regularly (GTEEX-HF). The exercise modality was treadmill running. RESULTS: After 15 wk, GTE alone and regular exercise alone caused a 47 and 24% reduction in body weight gain induced by the high-fat diet, respectively, and when combined, resulted in an 89% reduction. In visceral fat accumulation, GTE alone, exercise alone, and their combination caused a 58, 37, and 87% reduction, respectively. Indirect calorimetry showed that the GTEEX-HF group had the highest energy expenditure and fat utilization in the sedentary condition after 4 wk. Furthermore, the GTEEX-HF group utilized more fat than the EX-HF group during exercise. GTE supplementation increased hepatic fatty acid oxidation both in the exercised and nonexercised groups. In addition, when combined with regular exercise, GTE supplementation also stimulated skeletal muscle fatty acid oxidation. CONCLUSION: In conclusion, dietary GTE and regular exercise, if combined, stimulate fat catabolism not only in the liver but also in skeletal muscle, and attenuate high-fat diet-induced obesity more effectively than each alone in C57BL/6J mice.

Molecular cloning and circadian regulation of cryptochrome genes in Japanese quail (Coturnix coturnix japonica).

The circadian system is thought to have three components: input, pacemaker (internal clock), and output. Cryptochromes (Cry) are important clock genes, and recent findings indicate that these genes not only act as circadian photoreceptors but are also essential components in the negative feedback of the circadian system. As a first step toward understanding the avian circadian system, the authors tried to clone Japanese quail homologs of mammalian Crys and analyze their expression patterns in different circumstances. Partial cDNAs of qCry1 and qCry2, which are homologs of mammalian Cry1 and Cry2, respectively, were obtained and their gene expressions were analyzed. Both qCry1 and qCry2 mRNAs were present in all the tissues examined. The oscillation patterns of the qCry1 transcripts were tissue specific and generally showed robust changes between daytime and nighttime; except for lung and testis tissues (which showed no detectable changes between daytime and nighttime), daytime levels were higher in all of the tissues examined. This rapid oscillation in qCry1 persisted through constant darkness or constant illumination, indicating that an endogenous clock controls these changes. In contrast, the expression of qCry2 did not oscillate in any tissue examined. In addition, in tissues of the pineal gland and eye, unexpected light exposure in the dark period was able to block the decrease in qCry1 transcripts or induce its expression. These findings, in conjunction with the established roles of CRYs in other species, led the authors to propose that in the circadian system, qCRYs may play important roles similar to the known roles of CRYs of other species, such as acting as circadian photoreceptors and as components of the circadian system.