• Natural Product Sciences
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• v.8 no.2
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• pp.44-47
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• 2002

The effects of Eurycoma longifolia Jack on masculine copulatory behaviour were studied in the middle aged male Sprague-Dawley rats, 9 months old and retired breeders after dosing them with 500 mg/kg twice daily for 10 days prior to test. The test lasted for 30 minutes after a 20 minute adaptation period, was carried out on the 11th day during the dark phase of the light-dark cycle (2000-0700 hours) and in subdued light, using a modified copulation cage but with the presence of a piece of mirror of appropriate size to facilitate observation. Results showed that the mean values of EL-1, EL-2 and EL-3 of the control middle aged male rats were 103.20 sec, 91.21 sec and 80.00 sec but were significantly (p<0.05) increased to 118.40-120.20 sec, 101.24-171.28 sec and 100.42-110.21 sec respectively in the methanol-chloroform, methanol-butanol-water and methanol-butanol treated middle aged male rats. However, further results also showed that PEI-1 and PEI-2 of the control middle aged male rats were 182.30 sec and 257.2 sec but were significantly (p<0.05) decreased to 100.42-121.31 sec and 40.21-132.31 sec respectively in the methanol-chloroform-butanol-water and methanol-butanol treated middle aged male rats. In conclusion, this study showed that although E. longifolia Jack continued to enhance the sexual activity of the middle aged male rats by extending the duration of coitus and decreasing the refractory period between the different series of copulation, but to a smaller degree as compared to sexually active, adult male rats (Ang and Sim, 1997).

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1023-1028
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• 2007

This study was designed to determine whether dietary glutinous barley (GB) affects lipid metabolism in middle-aged rats previously fed a high-fat diet. To induce obesity, 20 male 9-month-old Sprague Dawley rats were raised for 1 month on a diet containing 20%(w/w) lipid. The rats were allocated to 1 of 2 groups of 10 rats each and for the subsequent 2 months were fed an 8%(w/w) lipid diet containing well-milled rice (WMR) or GB powder. Rats fed the GB diet had significantly lower concentrations of plasma triglyceride, plasma total cholesterol, and liver cholesterol than rats fed the WMR diet. Fecal excretions of triglyceride and bile acids were significantly greater for the GB group than for the WMR group. In conclusion, dietary GB has positive effects on lipid metabolism: it decreases plasma cholesterol concentration by increasing fecal excretion of bile acids.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.5
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• pp.283-287
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• 2006

Although estrogen is known to playa role in fatty acid metabolism, it remains unclear whether fatty acid oxidation in mature female rats differs from fatty acid oxidation in peri-pubertal young rats. In this study, we measured fatty acid metabolism in the skeletal muscles and livers of 5 and 50 weeks old male and female rats. The rate of palmitate oxidation in the liver and gastrocnemius red in the 50-week-old female rats were elevated as compared to the 5-week-old females, whereas there were no differences in the male rats. The rate of palmitate oxidation in the gastrocnemius red was correlated inversely with intra-abdominal fat mass in the 5-week-old male and female rats, whereas the palmitate oxidation rate was positively correlated with fat mass in the liver and gastrocnemius red in the 50-week-old rats. HOMA-IR and plasma insulin levels were positively correlated with intra-abdominal fat mass in the pooled 50-week-old male and female rats, but this correlation was not apparent in 5-week-old rats. In summary, the rate of fatty acid oxidation measured in the middle-aged adult female rats was significantly higher than those measured in the peri-pubertal young female rats. This difference may be attributed to the influence of ovarian hormones.

• Biomolecules & Therapeutics
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• v.6 no.4
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• pp.337-344
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• 1998

The objective of the present study was to investigate the effect of senescence on the binding properties of muscarinic receptors in the neostriatum of young (3 months), middle-aged (18 months) and aged (33 months) male Fischer 344 x Brown Norway hybrid rats by employing direct binding of selective radiolabeled antagonists. Using the selective M, muscarinic receptor antagonist, $[^3H]$AF-DX384, as the ligand, no significant difference in the maximal receptor density (Bmax) was observed in the neostriatum among any age-groups. In contrast, with the selective M, receptor antagonist, $[^3H]$4-DAMP, a significant increase in the number of muscarinic receptors was observed in neostriatal membrane fractions prepared from the aged animals relative to that observed in the young rats. For each ligand there was no age-related change in its affinity (Kd) for the muscarinic receptors. These results indicate that the observed age-related changes in the muscarinic receptor density may not be necessarily decremuntal and depend upon the muscarinic receptor subtype examined.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.633-641
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• 2017

The aim of this study is to investigate the effects of intermittent ladder-climbing exercise training on mitochondrial biogenesis and ER stress of the cardiac muscle in high fat diet-induced obese middle-aged rats. We induced obesity over 6 weeks of period in 40 male Sprague-Dawley rats around 50 weeks old, and were randomly divided into four experimental groups: chow, HFD, exercise+HFD, and exercise+chow. The exercising groups underwent high-intensity intermittent training using a ladder-climbing and weight exercise 3 days/week for a total of 8 weeks. High-fat diet and concurrent exercise resulted in no significant reduction in body weight but caused a significant reduction in visceral fat weight (p<0.05). Expression of $PPAR{\delta}$ increased in the exercise groups and was significantly increased in the high-fat diet+exercise group (p<0.05). Among the ER stress-related proteins, the expression levels of p-PERK and CHOP, related to cardiac muscle damage, were significantly higher in the cardiac muscle of the high-fat diet group (p<0.05), and were significantly reduced by intermittent ladder-climbing exercise training (p<0.05). Specifically, this reduction was greater when the rats underwent exercise after switching back to the chow diet with a reduced caloric intake. Collectively, these results suggest that the combination of intermittent ladder-climbing exercise training and a reduced caloric intake can decrease the levels of ER stress-related proteins that contribute to cardiac muscle damage in obesity and aging. However, additional validation is required to understand the effects of these changes on mitochondrial biogenesis during exercise.

• 한국체육학회지인문사회과학편
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• v.55 no.6
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• pp.691-700
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• 2016

The purpose of this study was to investigate the effects of long-term endurance exercise or resistance exercise training on muscle anabolic/catabolic pathway. 50wks-old male Wistar rats(n=30) were randomly assigned for 3 groups (sedentary, endurance exercise, resistance exercise group). After 12-week of training, plantaris muscles were dissect to measure protein level. Akt/mTOR signal-related proteins were significantly increased only after resistance exercise training, but catabolic signal-related proteins, FoxO1 and MuRF1, were significantly decreased after resistance and endurance exercise training. After endurance exercise training, AMPK and PGC-1α protein levels were significantly increased. Therefore, the endurance exercise training has been shown to affect the protein balance of aging muscle through inhibition of muscle protein catabolism. The present results suggest the possibility that not only resistance exercise but also endurance exercise will be affectable to keep or increase muscle volume and capacity of middle-aged people.

• Korean Journal of Veterinary Research
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• v.35 no.3
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• pp.505-513
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• 1995

Seventy wild rats were caught from Seoul city, Kyonggi, Kangwon, Honam, and yongnam provinces. All of them were in same species, Rattus norvegicus, except two R rattus from Kyonggi province. Seventy sera from wild rats were studied by immunofluorescent antibody assay for evidence of infection by spotted fever group rickettsia. The antidody prevalance was 37.14%(26/70) for spotted fever group rickettsia. The sero-prevalence rates for spotted fever group rickettsia antibody was the hightest in Kyonggi province with 55.56%(10/18), yongnam province with 50.00%(10/20), Kangwon province with 25.00%(2/8), Seoul city with 18.75%(3/16), and Honam province with 12.50%(1/8). The sero-positive rates difference between sexes were higher in female with 46.15%(12/26) than in male with 31.81%(14/44) for spotted fever group rickettsia. Twenty six of 68 Rattus norvegicus with antibody for spotted fever group rickettsia were in subadult with 50.00%(6/12), young adult with 38.89%(7/18), middle-aged adult with 35.29%(6/17), and old adult with 33.33%(7/21). No antibody was detected from R rattus.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.307-315
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• 2022

Since attaining middle age, many patients suffer from the post-micturition dribble (PMD) syndrome but do not receive proper treatment. This is because the etiology and treatment mechanisms of PMD differ from conventional lower urinary tract symptoms. Several pathophysiologies have been proposed, but the mechanisms we observed are the weakening of the bulbocavernosus muscle and dilation of the urethra due to atrophy of the cavernosal tissue. This study investigates the mechanism of PMD by observing anatomical changes in the corpus cavernosum and urethra. SD male rats were categorized by age into the young rats group (8 weeks old) and the old rats group (24 months or more). The ratio area of the bulbous urethra and corpus cavernosum to the total penis was statistically significant between both groups (P<0.05). Significant differences were obtained between the two groups for restored smooth muscle contents and several other parameters related to PMD mechanisms (nNOS, α-SMA) (P<0.05). The changes in size and parameters of the urethra and corpus cavernosum in young and old rats were confirmed. The results from this study are expected to contribute to the study of PMD in the future.