Journal of Yeungnam Medical Science

Original Articles

Effect of Paraxanthine on Body Fat Reduction and Insulin Sensitivity in Monosodiun Glutamate-Obese Rats: Jae-Kyung Song, So-Young Park, Jong-Yeon Kim, Hee-Sun Kim, Yong-Woon Kim; Yeungnam Univ J Med. 2007;24(2 Suppl):S481-492. Published online December 31, 2007; DOI: https://doi.org/10.12701/yujm.2007.24.2S.S481

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Purpose：To evaluate the effects of body fat reduction on insulin sensitivity, it was measured the glucose disappearance rate, glucose infusion rate, and hepatic glucose production rate after paraxanthine (1,7-dimethylxanthine, metabolite of caffeine) treatment in monosodium -L-glutamate (MSG)-obese rats. Materials and Methods：Obesity was induced by neonatal (2, 4, 6, 8, 10 days) injection of MSG(4 g/kg, subcutaneously) for 15 weeks. MSG-obese rats showed severe fat deposition in subcutaneous and intraabdominal cavity, shortened body length, normoglycemia, hyperinsulinemia, and high FFA level. Insulin sensitivity was assessed with hyperinsulinemic euglycemic clamp technique under anesthesia with pentothal sodium. Plasma insulin concentration was clamped at 100　μU/ml by continuous insulin infusion (1.5 mU/kg/min). At steady state, the glucose disappearance rate and glucose infusion rate were decreased and the hepatic glucose production rate was increased in the MSG-obese rats compared to the normal rats.
Results
：At 15 weeks of age, paraxanthine (15 mg/kg) was administered with ephedrine (60 mg/kg) via per oral for 15 consecutive days. Body fat mass of the paraxanthine treated rats was decreased about 29.6% in the MSG-obese and 6.3% in the normal rats compared with the control rats during 15 days. In the paraxanthine treated MSG-obese rats, the fasting insulin level was significantly (p<0.05) decreased and the glucose infusion rate was significantly (p<0.05) increased compared to that of the MSG-control rats, however the glucose disappearance rate showed increasing tendency and the hepatic glucose production rate showed decreasing tendency compared to that of the MSG-control rats.
Conclusion
：These results suggest that paraxanthine exerts an anti-obesity effect and improve insulin sensitivity in rats with MSG-induced obesity.

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Sesamolin Alleviates Nonalcoholic Fatty Liver Disease through Modulating Gut Microbiota and Metabolites in High-Fat and High-Fructose Diet-Fed Mice
Jing Yu, Hao Sun, Yang Yang, Yaping Yan
International Journal of Molecular Sciences.2022; 23(22): 13853. CrossRef

The Effect of Long Chain N-3 Polyunsaturated Fatty Acids on Development of Collagen-induced Arthritis in Rats.: Kyung Ho Shin, Se Dong Kim, Hwan Jin Jeon, Eung Chan Jang, Suck Kang Lee; Yeungnam Univ J Med. 2002;19(1):39-48. Published online June 30, 2002; DOI: https://doi.org/10.12701/yujm.2002.19.1.39

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Abstract PDF: BACKGROUND
The treatment of rheumatoid arthritis still depend on conserve therapy in major. Recent studies report that n-3 polyunsaturated fatty acids(PUFA) could modulate the incidence and progress of arthritis. The purpose of this study was to investigate the effects of n-3 PUFA on the development of collagen-induced arthritis in rats. MATERIALS AND METHODS: Female Louvain rats were used for this experiment. Rats were randomly assigned into either normal(n=8) or collagen-immunized groups, and collagen immunized groups were divided into control(n=8, normal diet) and n-3 PUFA(n=8, 5% n-3 PUFA in diet) groups. One week after feeding n-3 PUFA to rats, they were immunized with type II collagen emulsified in incomplete Freund's adjuvant into tail and back. Development of arthritis was confirmed by x-ray and microscopic examination. RESULTS: Incidence of arthritis at the 5th week after immunization was 38% in control and 0% in n-3 PUFA. Rats with arthritis showed edema in hind paws and inflammation in synovial membrane of the knee joint. Plasma glucose and insulin were not changed by both of immunization and diet. Plasma triglycerides and cholesterol concentrations were decreased by n-3 PUFA. CONCLUSION: n-3 PUFA may prevent or treat collagen-induced arthritis in rats. Further studies are needed for action mechanism of it.

Effect of Exercise on Antioxidant Enzyme Activities of Skeletal Muscle and Liver in STZ-diabetic Rats.: Kwang Ho Seok, Suck Kang Lee; Yeungnam Univ J Med. 2000;17(1):21-30. Published online June 30, 2000; DOI: https://doi.org/10.12701/yujm.2000.17.1.21

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Abstract PDF: BACKGROUND
The purpose of the present study was to investigate the effect of exercise on the activities of antioxidant enzymes, superoxide dismutase(SOD), glutathione peroxidase(GPX) and catalase(CAT) of skeletal muscle(gastrocnemius) and liver in streptozotocin(STZ) induced diabetic rats. The malondialdehyde(MDA) concentration was also measured as an index of lipid peroxidation of the tissues by exercise-induced oxidative stresses in the diabetic rats. MATERIAL AND METHODS: Male Sprague-Dawley rats were randomly divided into control and STZ-induced diabetic rats. The STZ in citrate buffer solution was injected twice at 5 days intervals intraperitoneally(50, 70 mg/kg respectively). On the 28th day after the first STZ injection, the diabetic animals were randomly divided into pre- and post-exercise groups. The exercise was introduced to the rats of post-exercise group by treadmill running till exhaution with moderate intensity (VO2max: 50-70%) of exercise. The duration of average running time was 2 hours and 19 minutes. RESULTS: The blood glucose concentration was increased(p<0.001) and plasma insulin concentration was decreased(p<0.001) in the diabetic rats. The glycogen concentration in the muscle and liver was decreased by exhaustive exercise in the diabetic rats(p<0.001). In the skeletal muscle, the activities of GPX was increased(p<0.05) and the activities of SOD and CAT were not changed in the diabetic rats compare to the control rats. The activities of GPX was not changed by exercise but the activities of SOD(p<0.01) and CAT (p<0.01) were decreased by exercise in the diabetic rats. The concentration of MDA was not changed by exercise in diabetic rats. and the values of pre-exercise and post-exercise diabetic rats were not different from the value of control rats. In the liver, the activities of SOD was decreased(p<0.01) and the activities of GPX and CAT were not changed in diabetic rats compared to the values of control rats. The activities of SOD, GPX and CAT were not changed by exercise in diabetic rats but the the slight decreasing tendency of the activity of SOD was observed. The MDA concentration was increased in the diabetic rats compared to the values of control rats(p<0.001) but there was no change of MDA concentration by exercise in diabetic rats. CONCLUSIONS: In summary, the exhaustive physical exercise has not been shown to impose oxidative stress on skeletal muscle due to oxygen free radicals regardless of decreament of SOD and CAT in the diabetic rats. In liver tissue, the tissue damage by oxidative stress was observed in diabetic rats but the additional tissue damage by the exhaustive physical exercise was not observed.

Utilization of Supercompensated Glycogen of Hindlimb Muscles during Strenous Exercise in Rats.: Chun Bae Jun, Jong Chul Ahn, Dae Deup Song, Suck Kang Lee; Yeungnam Univ J Med. 1997;14(1):137-154. Published online June 30, 1997; DOI: https://doi.org/10.12701/yujm.1997.14.1.137

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Abstract PDF: The aim of the present investigation has been to evaluate the depletion pattern of the supercompensated glycogen of hindlimb muscles during strenous exercise in rats. The plan of the maximizing muscle glycogen stores is based on the fact that a glycogen-depleted muscle by exercise will have an increased avidity for glycogen when exposed to a high carbohydrate diet. The glycogen concentration of soleus, red gastrocnemius and plantaris muscle, and liver was measured at 0, 30 and 60 minutes during treadmill exercise. The experimental animals were divided into 5 group - Normal(N), Control(C), 1Hour(1HR:after 1hour of glucose ingestion), 2Hour(2HR:after 2hour of glucose ingestion) and Exercise-1Hour(EX-1HR:glucose ingestion after 1 hour of preloading treadmill exercise)group - for glycogen storage study. The glycogen concentration of soleus, red gastrocnemius and plantaris muscles in N group was 4.57+/-0.34, 5.11+/-0.24 and 6.55+/-0.20 mg/gm wet wt., respectively. The glycogen concentration of soleus and red gastrocnemius in EX-1HR group were about 1.9 and 1.8 times than that of N group, respectively, but the concentration of plantaris was not higher than that of N group. The glycogen concentration of liver in N group was 41.0+/-1.47mg/gm wet wt. and the concentration of the overnight fasted C group wad only 2.9% of the value of N group. The level of glycogen concentration of liver in the other glucose ingested groups(1HR, 2HR, including EX-1HR) was within 19 - 32% of that of N group. The blood glucose concentration of EX-1HR group was higher than that of N group, the plasma free fatty acid concentration of C and 2HR group was higher than that of N group, and the plasma insulin concentration of EX-1HR group was higher than that of N group. The concentration of supercompensated glycogen of soleus and red gastrocnemius were rapidly decreased during 30 minutes of exercise but there was almost no changes of the concentration during the other 30 minutes of continuing exercise. The concentration of N group during 30 minutes of exercise was decreased but more slowly than those of EX-1HR group. The remaining level of glycogen after 60 minutes of exercise in EX-1HR group was higher than that of N group. Taken together, the mobilization of endogenous muscle glycogen at the first stage of exercise was proportioned to the intial level of glycogen concentration, and later on, when exercise continued, the muscle glycogen level was stabilized. And the remaining level of supercompensated muscle glycogen after 60 minutes of exercise was higher than that of normally stored glycogen level. The mobilization of the glycogen stroed in slow and fast oxidative muscle fibers is faster than in the fast glycolytic muscle fibers during strenous exercise.

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