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Biomedical subjects

E V Macková

Publications and source records attributed to E V Macková.

10 recordsLinked to original sources

Effect of exercise on muscle fibre composition and enzyme activities of skeletal muscles in young rats.

Young Wistar rats underwent dynamic (D) or static (S) exercise from the 5th to 35th day after birth. Histochemical and biochemical analysis were performed in the extensor digitorum longus (EDL) and the soleus muscle (SOL). Lactate dehydrogenase (LDH) (regulating anaerobic metabolism) and citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase (HAD) (both regulating aerobic metabolism) activities were determined spectrophotometrically. An increase of the fast oxidative-glycolytic (FOG) muscle fibres was found in the slow SOL muscle in both trained groups, i.e. by 10% in group D and by 7% in group S in comparison with the C group. The EDL muscle fibre distribution did not differ from those of control animals in respect to the slow oxidative (SO) fibre type. A higher percentage of FOG fibres by 19% was found in group D contrary to a decreased number of the fast glycolytic (FG) muscle fibres in this trained group. The greatest increase of CS (EDL 185%, SOL 176%) and HAD (EDL 83%, SOL 178%) activities were found in group D as compared with control group (C). Only small differences were observed in LDH activity. The values of characteristic enzyme activity ratios show that dynamic training resulted in an elevation of oxidative capacity of skeletal muscle, while the static load led preferentially along the glycolytic pathway. It may be concluded that an adaptive response to the training load during early postnatal development is different due to the type of exercise (dynamic or static) and/or the type of skeletal muscle (fast or slow).

3-Hydroxyacyl CoA Dehydrogenases↗

EMG activity in "compensatory" muscle hypertrophy.

The functional elimination of synergistic muscles leads to dramatic muscle hypertrophy. However, neither resting EMG activity recorded by an implanted electrode array, nor activity during locomotion have substantiated the assumption that the hypertrophy in the rat soleus muscle is caused by hyperactivity.

Adaptation, Physiological↗

The relationship between anaerobic performance and muscle metabolic capacity and fibre distribution.

Relationships between functional anaerobic indicators and the character of cellular muscle energy metabolism were studied. Twelve untrained male students were tested by a specific anaerobic test on the treadmill. The mean values of the anaerobic test were as follows: blood lactate 10.69 mmol . 1(-1), running speed 16.08 km . h-1 and duration 92.67 s. The average distribution of muscle fibres (m. vastus lateralis) was: type I 52.2%, type II A 29.0% and type II B 18.8%. The mean enzyme activity values were: triosephosphate dehydrogenase (TPDH) 4.67 mu kat . g-1 w.w., lactate dehydrogenase (LDH) 5.76 mu kat . g-1 w.w, citrate synthase (CS) 0.21 mu kat . g-1 w.w. and hydroxyacyl-CoA dehydrogenase (HAD) 0.12 mu kat . g-1 w.w. Significant negative correlations were found between delta LA and CS (r = 0.64) and % of fibre type II B and CS (r = 0.78) and positive correlations between % of fibre type I and CS and/or HAD (r = 0.60 and r = 0.62, respectively).

3-Hydroxyacyl CoA Dehydrogenases↗

Lysosomal and energy enzyme activities in hypertrophied rat soleus muscle after denervation.

Muscle hypertrophy was induced in the soleus muscle of young rats by tenotomy of the gastrocnemius and plantaris muscles. Three and 7 days afterwards the sciatic nerve was sectioned. The loss of weight of muscles subjected to this combined procedure three days after denervation was 30-40%. Lysosomal enzyme activities (acid phosphatase, alpha-glucosidase, beta-galactosidase and N-acetyl-beta-D-glucosaminidase) and energy enzyme activities (lactate dehydrogenase, LDH, triose-3-phosphate dehydrogenase, TPDH , D-hexokinase, HK and citrate synthase, CS) were determined 3 days after denervation, 3, 7 and 10 days after hypertrophy had been induced and 3 days after denervation of hypertrophying muscles on day 3 and 7. Normal non-operated rats of corresponding body weight served as controls and their enzyme activities were estimated on the same day. In the course of muscle hypertrophy, the 4 lysosomal enzyme activities increased progressively. Although 3 days' denervation of control muscles did not alter lysosomal enzyme activities, denervation of hypertrophying muscles greatly enhanced the activity of these enzymes. Enzymes of energy metabolism were affected to a lesser degree. The results suggest that denervation of hypertrophying muscles causes more extreme changes in muscle weight and lysosomal enzyme activities than denervation alone. The possible implications of this finding are discussed in relation to the rapid atrophy.

Animals↗

Muscle enzyme activities and fibre composition (m. vastus lateralis) and efficiency of the cardiorespiratory system in cross-country skiers.

Fourteen male cross-country skiers (class I and II, average age 20.5 years) were examined by biochemical and histochemical methods. The activity of selected enzymes of energy metabolism and the percentage ratio of different types of muscle fibres (m. vastus lateralis) were assessed. Furthermore, the maximum values of the cardiorespiratory system and post-loading pH and blood lactate were determined after performance on a treadmill. The mitochondrial enzyme activities were relatively high with a considerable scatter in the values of HOADH activity. The glycolytic enzyme activities were on the same level as in subjects not engaged in sports. The percentage composition of muscle fibres was as follows: FG - 7.56 %, FOG - 30.65 % and SO - 61.79 %. Oxygen consumption VO2 max.kg-1 was 67.44 ml.min-1, pulse oxygen 24.76 ml, post-load pH 7.24 and blood lactate concentration 6.98 mmol.l-1. There was positive correlation between CS enzyme activity and oxygen uptake (VO2 max), pulse oxygen and percentage of SO muscle fibres. The mean values found in the athletes examined in the present study corresponded to values of middle distance runners.

Adult↗

Enzyme activity patterns of energy metabolism in skiers of different performance levels (M. quadriceps femoris).

Changes in the activity of muscle enzymes of energy metabolism were studied in two groups of skiers (A, B) with a different sports performance (triosephosphate dehydrogenase-TPDH, lactate dehydrogenase-LDH, glycerol-3-phosphate dehydrogenase-GPDH, hexokinase-HK, malate dehydrogenase-MDH, citrate synthase-CS, hydroxyacyl,CoA dehydrogenase-HOADH). 1. In a group of ski-runners (A) significantly higher activities of CS, MDH, HOADH in the preparatory period (October) and also at the end of the competition period (March) were found in athletes with higher sports performance. 2. Significantly lower activities of LDH, GPDH, MDH, CS, HOADH were found in downhill skiers (group B). 3. Some significant correlations were established, both between the activities of individual enzymes (TPDH, GPDH, HK, CS, HOADH) and between the enzymes and indicators of functional capacity (MDH, CS, HOADH, VO2max, HRmax, O2-pulse max, body fat, laboratory performance).

Body Composition↗

Some hormonal factors (hypophysectomy, castration and testosterone administration) modifying the course of "compensatory" muscle hypertrophy in the rat.

1. Maximum compensatory hypertrophy of the soleus and plantaris muscle in male rats is attained seven days after tenotomy of the gastrocnemius muscle (39% and 9% respectively). When tenotomy of the gastrocnemius was performed seven days ater hypophysectomy, hypertrophy in these two muscles was aproximately half that found in control animals. 2. After 81-day castration of young male rats the weight of the saleus and plantaris was reduced and hypertrophy following tenotomy of the gastrocneumius muscle did not develop. 3. Chronically castrated rats received testosterone two weeks prior to tenotomy of the gastrocnemius and a week during the muscle hypertrophy phase. Hypertrophy of the soleus in castrated rats which had received testosterone seven days after tenotomy of the gastrocnemius was 25% as compared with muscles of castrated animals. The corresponding value in the plantaris muscle was 10%. 4. These results indicate that even calf muscles of the rat, namely the soleus and plantaris muscles, are significantly affected by testosterone under these conditions, although it is not, as yet, clear whether its action is direct or indirect.

Animals↗

Satellite cells of the rat soleus muscle in the process of compensatory hypertrophy combined with denervation.

Compensatory hypertrophy was induced in the rat soleus muscle by sectioning the tendon of the ipsilateral gastrocnemius and plantaris muscle. Seven days after tenotomy of synergistic muscles, when soleus hypertrophy attains about 40%, the number of satellite cells (expressed as percentage of all muscle nuclei found in the same cross-sections) as revealed by electron microscopy, was increased from 5.8+/-0.06% in the normal soleus muscle to 16.6+/-1.26%. After four days' denervation of the soleus muscle the percentage of satellite cells was increased to 7.2+/-0.62%. In experiments where hypertrophy of the soleus muscle was combined with denervation three days after tenotomy of synergists, and examined after another four days (during which time it loses, as has previously been shown, over 40% of its predenervation weight), the number of satellite cells was greatly increased to 29.9+/-3.42%. This increase is apparently due to two independent processes which take place during the first postoperative period: a) mitotic division of satellite cells during the early stages of compensatory hypertrophy and b) pinching off of muscle nuclei from rapidly atrophying muscle fibres due to subsequent denervation. Activation of satellite cells was mainly manifested by expansion of smooth and especially of rough endoplasmic reticulum, a rich Golgi complex, high pinocytotic activity, increased number of ribosomes and by nuclear changes. Concomitantly with the increased number of satellite cells, proliferation of fibroblasts, macrophages and mast cells could be observed.

Animals↗