Time filter

Source Type

Okayama-shi, Japan

International Pacific University is a private university in Higashi-ku, Okayama, Japan, established in 2007. Wikipedia.

Aizawa K.,Center for Disease Biology and Integrative Medicine | Iemitsu M.,International Pacific University | Maeda S.,University of Tsukuba | Otsuki T.,St. Catherine University of Japan | And 5 more authors.

Androgens, such as testosterone, play important roles in regulation of diverse physiological process of target tissues. Recently, we reported that steroidogenic enzymes exist in skeletal muscle and regulate local production of testosterone in response to exercise. Testosterone is transformed into a bioactive androgen metabolite, dihydrotestosterone (DHT) by 5α-reductase. However, it is unclear whether exercise stimulates local bioactive androgen metabolism in the skeletal muscle in both sexes. In the present study, we examined sex differences in the levels of dehydroepiandrosterone (DHEA), free testosterone, DHT, and steroidogenesis-related enzymes 5α-reductase and androgen receptor (AR) in rat's skeletal muscle before and after a single bout of exercise. Basal muscular free testosterone and DHT levels were higher in males than females, whereas the levels of DHEA did not differ between the sexes. Muscular DHEA, free testosterone, and DHT levels were increased in both sexes after the exercise. There were no differences of 5α-reductase and AR transcripts and proteins between the sexes, and the expression of 5α-reductase was significantly increased in both sexes after the exercise. Finally, the expression of AR was significantly higher in female rats, but not in males after the exercise. These data suggest that acute exercise enhances the local bioactive androgen metabolism in the skeletal muscle of both sexes. © 2009 Elsevier Inc. All rights reserved. Source

Imamura H.,Nagasaki International University | Nagata A.,Nagasaki International University | Oshikata R.,Seika Womens Junior College | Yoshimura Y.,Beppu University | And 4 more authors.
International Journal of Sports Medicine

Many of the published data on the lipid profile of athletes is based on studies of endurance athletes. The data on soccer players are rare. The purpose of this study was to examine serum high-density lipoprotein cholesterol subfractions and lecithin:cholesterol acyltransferase activity in collegiate soccer players. 31 well-trained male collegiate soccer players were divided into 2 groups: 16 defenders and 15 offenders. They were compared with 16 sedentary controls. Dietary information was obtained with a food frequency questionnaire. The subjects were all non-smokers and were not taking any drug known to affect the lipid and lipoprotein metabolism. The offenders had significantly higher high-density lipoprotein cholesterol, high-density lipoprotein2 cholesterol, and apolipoprotein A-I than the defenders and controls, whereas the defenders had the significantly higher high-density lipoprotein2 cholesterol than the controls. Both groups of athletes had significantly higher lecithin:cholesterol acyltransferase activity than the controls. The results indicate that favorable lipid and lipoprotein profile could be obtained by vigorous soccer training.© Georg Thieme Verlag KG . Stuttgart . New York. Source

Miyaji T.,Tsukuba Center Inc. | Sato M.,Tsukuba Center Inc. | Maemura H.,International Pacific University | Takahata Y.,Tsukuba Center Inc. | Morimatsu F.,Tsukuba Center Inc.
Journal of the International Society of Sports Nutrition

Background: Carnosine is a dipeptide that improves exercise performance. The carnosine synthesis mechanism through carnosine and ß-alanine ingestion remains unclear. Therefore, we investigated the tissue distribution of carnosine synthase, ATP-grasp domain-containing protein-1 (ATPGD1) mRNA, and ATPGD1 and carnosine specific dipeptidase (CN1) gene expression profiles in mice that were given carnosine or ß-alanine orally.Methods: ddY mice (7-week-old) were randomly divided into three groups (n = 6 to 8 animals per group) and were orally given 2 g/kg body weight of carnosine, ß-alanine, or water. After 15, 30, 60, 120, 180, or 360 min of treatment, the tissues (brain, blood, liver, kidneys, olfactory bulbs, hindleg muscles) were collected. The obtained tissues measured the expression of ATPGD1 and CN1 genes using quantitative PCR methods.Results: The ATPGD1 gene was expressed in muscle and to a lesser extent in brain. The expression of ATPGD1 in the vastus lateralis muscle increased significantly at 180 min (P = 0.023) after carnosine ingestion and 60 (P = 0.023) and 180 min (P = 0.025) after ß-alanine ingestion. Moreover, the carnosine group showed a significantly increased renal expression of the CN1 gene 60 min after ingestion (P = 0.0015).Conclusions: The ATPGD1 gene showed high expression levels in brain and muscle. The ß-alanine or carnosine administration significantly increased ATPGD1 and CN1 expression in mice. © 2012 Miyaji et al; licensee BioMed Central Ltd. Source

Hayata G.,International Pacific University | Miyakawa T.,Kawasaki University of Medical Welfare
Japanese Journal of Physical Fitness and Sports Medicine

The purpose of this study is to show the kinetic effect on the stop-jump movement in wearing overlap length change of the knee joint supporter. Ten young health males volunteered as subjects for this study. Three-dimensional videographic and ground reaction force data in a stop-jump task were collected in three conditions. Overlap length of supporter, peak ground reaction force, peak knee flexion angle, peak knee extension torque at landing, peak jump height, peak jump velocity at takeoff were compared among conditions: high pressure condition, middle pressure condition and no supporter. The high pressure condition significantly increased peak knee flexion angle and peak knee extension torque at landing. It is considered that the high pressure condition enlarged the knee joint angle and the knee joint extension torque in stop task because the rigidity of the supporter increased. On the other hand, it was suggested that the pressure change of wearing the knee joint supporter don't affect jump performance. Source

Imamura H.,Nagasaki International University | Iide K.,International Pacific University | Yoshimura Y.,Beppu University | Kumagai K.,Nagasaki International University | And 5 more authors.
Journal of the International Society of Sports Nutrition

Background: There are two main playing positions in rugby (backs and forwards), which demonstrate different exercise patterns, roles, and physical characteristics. The purpose of this study was: 1) to collect baseline data on nutrient intake in order to advise the athletes about nutrition practices that might enhance performance, and 2) to compare serum lipids, lipoproteins, apolipoproteins (apo), lecithin:cholesterol acyltransferase (LCAT) activity, and iron status of forwards and backs.Methods: The sporting group was divided into 18 forwards and 16 backs and were compared with 26 sedentary controls. Dietary information was obtained with a food frequency questionnaire. Results: There were significant differences among the three groups. The forwards had the highest body weight, body mass index, percentage of body fat (calculated by sum of four skinfold thicknesses), as well as the highest lean body mass, followed by the backs and the control group. The mean carbohydrate intake was marginal and protein intake was lower than the respective recommended targets in all three groups. The mean intakes of calcium, magnesium, and vitamins A, B1, B2, and C were lower than the respective Japanese recommended dietary allowances or adequate dietary intakes for the rugby players. The forwards had significantly lower high-density lipoprotein cholesterol (HDL-C) and HDL2-C than the backs and had significantly higher apo B and LCAT activity than the controls. The backs showed significantly higher HDL-C, HDL3-C, low-density lipoprotein cholesterol, and apo A-I, and LCAT activity than the controls. Four forwards (22%), five backs (31%), and three controls (12%) had hemolysis. None of the rugby players had anemia or iron depletion. Conclusion: The findings of our study indicate that as the athletes increased their carbohydrate and protein intake, their performance and lean body mass increased. Further, to increase mineral and vitamin intakes, we recommended athletes increase their consumption of green and other vegetables, milk and dairy products, and fruits. The forwards showed more atherogenic lipid profiles than the backs, whereas the backs showed not only anti-atherogenic lipid profile, but also showed more atherogenic lipid profile relative to the control group. Additionally, our study showed none of the rugby players experienced anemia and/or iron depletion. © 2013 Imamura et al.; licensee BioMed Central Ltd. Source

Discover hidden collaborations