Sex difference in enzyme activities of the skeletal muscle were examined in rats aged 10 and 35 weeks. At 10 and 35 weeks of age, animals were anesthetized with ether and weighed. M, gastrocnemius, m.extensor digitorum longus and m.soleus were removed from both legs under pentobarbital anethesia and weighed. These muscles were used for the determination of myosin ATPase activity, phosphofruktokinase (PFK) activity, succinate dehydrogenase (SDH) activity and non-collagenous protein (NCP) content.
The results were summarized as follows:
1) Thirty-five week-old rats had heavier body and muscle weights than 10-weekold rats in both sexes and males had significantly heavier body and muscle weights than females at both 10 and 35 weeks of age.
2) Similar tendency was observed with regard to total NCP content. Furthermore, it was found that total NCP content was positively correrated to muscle weight (r=0.871, r=0.909 and r=0.871 in m. gastrocnemius, m.extensor digitorum longus and m.soleus, respectively) . However, no significant difference in NCP content per wet weight was found between both sexes and between different age groups.
3) Myosin ATPase activity tended to be lower at 35 weeks of age than at 10 weeks of age, the tendency being the most prominent in the gastrocnemius muscle of male rat (p<0.05) . However, no significant sex difference in myosin ATPase activity was observed in three muscle examined in both age groups.
4) Although not statistically significant, mean PFK activity was slightly lower in 35-week-old rats than in 10-week-old rats, and there was no sex difference in PFK activity at both weeks of age.
5) SDH activity was significantly lower in 35-week-old rats than in 10-week-old rats except that there was no significant age difference in the gastrocnemius muscle of males. There was no significant sex difference in SDH activity in both age groups with an exception of the extensor digitorum longus muscle from 35-week-old rats, where males had significantly higher SDH activity than females.

1. The effect of thyroidectomy on histochemical properties of the extensor digitorum longus and soleus muscles was studied in rats. Two or 13 months after thyroidectomy animals were killed and muscle sections of 10μm thickness were stained for succinate dehydrogenase and myosin adenosine triphosphatase activities.
2. No significant difference of the body weight was found between the thyroidectomized and sham-operated control groups. There was also no significant difference in the muscle weight between the two groups except that 13 months after thyroidectomy the soleus muscle weight was significantly lower in the thyroidectomized group than in the sham-operated control group.
3. The measurement of muscle fiber diameter revealed that fast-twitch oxidative glycolytic fibers of the soleus muscle were smaller in the thyroidectomized group than in the sham-operated control group two or 13 months after thyroidectomy.
4. The percentage of fast-twitch fibers decreased significantly after thyroidectomy with a concomitant increase in the percentage of slow-twitch fibers in both the extensor digitorum longus and soleus muscles. This finding suggests the involvement of thyroid hormone in determining a phenotypic expression of muscle fiber type.
5. The results show that thyroidectomy-induced changes differ not only between the extensor digitorum longus and soleus muscles but also between same types of fibers from the two muscles. The results also indicate that thyroidectomy-induced changes depend on the period after thyroidectomy.

Postnatal changes of myosin light chain patterns and enzyme activities were examined in the fast extensor digitorum longus and slow soleus muscles of Wistar strain rats aged 5, 10 and 20 weeks. Sex differences in each parameter were also studied.
The results were summarized as follows:
1) The extensor digitorum longus muscle contained mostly the fast light chains (fLC 1, fLC 2, fLC 3) . However, small amounts of the slow light chains (sLC 1, sLC 2) were also found. There were no postnatal changes in myosin light chain patterns in the extensor digitorum longus muscle.
2) The soleus muscle contained slow and fast light chains (sLC 1, sLC 2, fLC 1, fLC 2, fLC 3) in 5 weeks of age, slow light chains being more predominant than fast light chains. There were an increase in the percentage of slow light chains and a concomitant decrease in the percentage of fast light chains with age. FLC 3 which was found at 5 weeks of age did not be detected in the soleus muscle from the 20-week-old rat.
3) PFK activity decreased significantly with age in the soleus muscle, whereas there was no postnatal changes in PFK activity in the extensor digitorum longus muscle.
4) There was a significant increase in SDH activity during growth in both the extensor digitorum longus and soleus muscles with the exception of the extensor digitorum longus muscle from the male rat.
5) The enzyme activity ratio (PFK/SDH) significantly decreased with age in all muscles with an exception of the extensor digitolum longus muscle from the male rat.
6) In the soleus muscle an increase in the relative amount of slow type myosin light chains and a decrease in the enzyme activity ratio (PFK/SDH) occurred coincidentally during postnatal growth.
7) In most cases no significant sex differences existed in myosin light chain pattern and enzyme activity examined.

Although icing treatment has been well accepted as aftercare in sports fields, the detailed mechanisms of the treatment is not fully understood. In this study, we investigated the effect of icing treatment on the recovery process of rat plantaris muscles with artificially induced muscle damage. Sixty male Wistar rats (8-weeks-old) were randomly assigned to three groups; control (CTL), bupivacaine-injected (BPVC), and icing treatment after BPVC (ICE). Icing treatment was applied for 20 min immediately after BPVC, and the treatment was used once per day for 3 days. The plantaris muscles were removed at 3, 7, 15, and 28 days after the muscle damage, then immunohistochemical and real time RT-PCR analysis were performed. In histochemical analysis, although significant changes were found in the relative muscle weight, cross-sectional area of muscle fiber, percentage of muscle fiber with central nuclei, and expressed immature myosin heavy chain isoforms after muscle damage, as compared to the CTL group, no differences were found between BPVC and ICE groups. In mRNA expression analysis, the ICE group had a significantly lower value of MyoD than the BPVC group at 3 days after the damage. Expression of IL-6 mRNA, which relates to muscle inflammation, indicated significantly higher value in BPVC, but not in ICE, than CTL groups at 7days after the damage. Furthermore, BKB₂ receptor, which relates to acute muscle soreness, indicated a significantly higher expression in BPVC than ICE groups at 3 days after the damage. These results suggest that icing treatment is effective to suppress muscle inflammation and soreness at an early stage of recovery from damage, but not effective for muscle regeneration at a later stage.

Myosin light chain patterns were examined in single fibers from the extensor digitorum longus (EDL) and soleus muscles of Wistar strain rats. The fiber type composition of both muscles was also determined to estimate the relationship between myosin light chain patterns and histochemical fiber types.
The results were summarized as follows ;
1. All of single fibers from the EDL muscle was typical fast type which contained fast light chains only (fLC 1·fLC 2·fLC 3), except that there was one mixed type fiber cotaining both fast and slow light chains (fLC 1·fLC 2·sLC 1·sLC 2) .
2. There were two myosin light chain patterns in single fibers from the soleus muscle. One was typical slow type which contained slow light chains only (sLC1·sLC 2) and the other, mixed type in which fast and slow light chains coexisted. Mixed type fibers were divided into eight groups based on the light chain composition. The percentage occurence of typical slow type and mixed type fibers was 35.4% and 64.6%, respectively.
3. The average percentage of type II fibers was 94.6% in the EDL muscle 5.4% in the soleus muscle.
4. These results suggest that both fast and slow skeletal muscles contain mixed type fibers. The results further imply that in slow skeletal muscle, myosin light chain pattern of mixed type occurs not only in type II but also in type I fibers.

It has been demonstrated that exercise induces heat shock proteins (HSPs) . However, no study has investigated changes in HSPs following endurance training at different speeds. Therefore, this study was designed to investigate the effect of treadmill training at different running speeds on induction HSPs. One group of male Wistar rats was assigned as a sedentary control, three groups were assigned for exercise training (10 m/min, 20 m/min and 30 m/min) and another three groups for one acute bout of exercise (10 m/min, 20 m/min and 30 m/min) . Each training group ran at each speed for 30 min/day, 5 days a week for 8 weeks. The acute exercise group performed the exercise only once. Forty-eight hours after the last exercise session was completed, the rats were sacrificed and the plantaris (PLA) and soleus (SOL) muscles were dissected. In the acute exercise group, the content of HSP72 in both the PLA and SQL increased (p<0.05) at all speeds, and the content of HSP60 increased significantly (p<0.05) at all speeds for the PLA, but not for the SOL. On the other hand, in the endurance group, the content of HSP72 and HSP60 in both muscles increased in 30 m/min groups. These results indicate that an increase in HSP72 and HSP60 by endurance training is induced by high intensity training in both muscles. This was not found to be the case with the acute exercise groups.

Eighty healthy males aged from 26 to 34 years were studied to evaluate the effects of regular physical training on body composition, respiratory functions, circulatory functions, blood constituents, and physical fitness. The physical training consisted of jogging, volleyball, handball, socker, judo, fencing, and others. The combination of these sports were assigned to all the subjects to be performed for 130 minutes every week-day from April, 1979 to January, 1980.
1) The subjects had, on the average, 518 g of carbohydrate, 125 g of protein including 74 g of animal protein, and 85 g of fat summing up to 3300 kcal a day. These nutrients intake was 30% to 50% excess over the normal value for male Japanese of the corresponding age. Body weight, however, did not change and body fat decreased in spite of large excess food intake. Serum HDL-cholesterol increased and atherogenic index decreased. These facts lead to a conclusion that the noxious effects of overeating can be cancelled by physical activity.
2) Pulse wave velocity of the aorta which reflects the elasticity of the aortic wall decreased. This means that changes in the physical property of the aorta due to aging process can be reversed through physical training. Decrease in pulse wave velocity dose not always mean the regression of atherosclerosis, but the additional findings such as decrease in body fat and in atherogenic index and increase in HDL-cholesterol support the possibility of regression of aterosclerosis by physical activity.
3) The results of physical fitness test indicated marked improvement of physical abilities which reflect muscular strength, muscular power, muscular endurance, body flexibility, agility, anaerobic power, and aerobic power.

This study was conducted to examine the prevalence of undernourished elderly in community-dwelling elderly people, and to analyze the correlation between under-nutritional status and health status and physical fitness of the elderly.The subjects comprised 1758 residents (757 men and 1001 women) aged 70 or over living in Itabashi-ku, Tokyo, who took part in an interview and biochemical blood examination as part of the “OTASHA-KENSHIN”. In this study, we set the ‘under-nutrition group’ as serum albumin level ≤ 3.8 g/dL (normal group serum albumin level ≥ 3.9 g/dL). Based on this standard, 124 subjects (72 men and 52 women) were found to be undernourished. Physical fitness was measured by handgrip strength, knee extension power, and walking capability (usual and maximal walking speed).The prevalence of undernourished elderly was significantly higher in men than in women, and in those living alone or with a spouse compared with those living with children. It became clear that the lifestyle and health status of the under-nutrition group was generally poor compared with those of the normal group. Handgrip strength and knee extension power were significantly lower in the under-nutrition group than in the normal group of men. Although usual and maximal walking speed tended to be lower in the under-nutrition group, there was no significant difference. In women, a significant difference in handgrip strength, knee extension power, and walking capability was not seen between the two groups.These results suggest that an intervention program for the undernourished elderly living in the community should target an improvement not only of nutrition but also of physical fitness.

In the present study, we investigated the effect of heat stress on disuse atrophy from changes in the muscle protein levels of desmin and calpain. Wistar strain female rats (6-8 months old) were randomly assigned to two experimental groups: control (C) and heat stress (H). One hindlimb of all animals was immobilized in plantar flexion with plaster. Before immobilization, animals in H group were placed in a heat chamber (42°C for 60 min). Following 6 days of immobilization, the soleus muscles were removed and analyzed. Although immobilization resulted in significant muscle atrophy in all experimental animals, the soleus weight-to-body weight ratio in immobilized limbs of H group was significantly higher compared to that of C group. Expression of desmin and HSP72 in the atrophied soleus muscle from C group was significantly lower compared with the contralateral muscle; but this was not the case in H group. Further, in C group, the ratio of autolyzed calpains I increased significantly in the atrophied muscle compared to the contralateral muscle. These results show that the effect of heat stress on disuse skeletal muscle atrophy is attributed to the decreasing degradation of desmin by suppressing the activation of calpain.

The present study was carried out to investigate differences in hormonal and metabolic responses to moderate exercise in the post-absorptive state and during a 33-hour fast. Secretory factors and the roles of regulatory hormones of carbohydrate and lipid metabolism during moderate exercise were assessed baesed on these data. Energy substrates in the blood (glucose, BG; lactate, LA; triglyceride, TG; free fatty acids, FFA; free glycerol, FG) and plasma hormones (ACTH; GH; Cortisol, Corti; glucagon, IRG; insulin, IRI) concentrations were measured from 12 h to 33 h during the fasting period (12: 00, 24: 00, 06: 00, 09: 00), and 3min, 10 min and 30min after moderate treadmill exercise (estimated 70-80% of VO₂max) for 20 min under fasting conditions between 09: 00 and 11: 00. These results (in the fasting experiment, Fast) were compared to the results on a normal diet (N-D) .
The results were as follows:
1. No differences in mean VO₂ and respiratory exchange ratio (RER) during exercise were observed between the Fast and N-D experiments. Mean heart rate during exercise in Fast was higher by 3.3±2.2 bpm (p<0.05) .
2. Serum FFA and FG concentrations were significantly higher as a results of 24-hour fasting than the values measured at the same time in N-D. No significant change in serum TG concentrations were observed in Fast. While BG and LA concentrations remained low, and in small changes occurred in then both during Fast.
3. Slightly higher levels of plasma ACTH, GH and IRG were found in Fast, but they were not significantly different from N-D. Plasma Corti concentrations gradually increased after 24 hours of fasting, and were 1.9 times higher at 09: 00 after 33 hours of fasting than on N-D. Plasma IRI levels, however, remained low, and the molecular ratio of IRG to IRI (IRG/IRI) was higher throughout Fast (1.8 to 10.6 times higher than on N-D ) .
4. Plasma ACTH, GH and Corti concentrations increased markedly after exercise, and remained high until 30 min on Fast. No significant change in IRG and depression of insulin secretion were demonstrated after exercise on both treatment.
5. Significant correlation between changes in plasma ACTH and Corti concentrations were observed throughout the experiments (Fast, r=0.562; N-D, r=0.528) .
6. All of the energy substrates except blood TG increased after exercise, and the net increases in LA and FG (Δ) on Fast were significantly higher than on N-D. Significant correlations between the changes in the concentrations of FFA and FG (Fast, r=0.745; N-D, r= 0, 696), LA and BG (Fast, r=0.689; N-D, r=0.623), and FFA and LA (Fast, r=0.579; N-D, r= 0.479) were detected throughout both experiments.
7. The coefficients of correlation between changes in plasma ACTH and FFA, and between BG and LA concentrations were higher on Fast than N-D. However, changes in plasma IRI and IRG concentrations were not directly correlated with any other changes in energy substrates in the blood in either treatment.
The results indicated that moderate exercise for 20 min after a 33-hour fast causes marked responses in ACTH, Corti and GH secretions. It appeared that Corti secretion de-pended on ACTH, and that Corti facilitated fatty metabolism during exercise on Fast. However, secretion factors and the role of GH during exercise remain a matter of conjecture.