Enzyme activity patterns of energy supplying metabolism in the quadriceps femoris muscle (vastus lateralis): sedentary men and physically active men of different performance levels

1. In 3 groups of men, differing as to the amount and intensity of physical training loads, increasing in the order "sedentary": "sporting": "athletic", enzyme activities were estimated in biopsy samples of m. quadriceps femoris (vastus lateralis). The enzymes were: Hexokinase (HK), NAD: glycerol-3-phosphate dehydrogenase (GPDH), triosephosphate dehydrogenase (TPDH), lactate dehydrogenase (LDH), citrate synthase (CS), NAD: malate dehydrogenase (MDH), and 3-hydroxyacyl-CoA dehydrogenase (HOADH). Indicators of laboratory performance and whole-body metabolic capacities (maximal oxygen consumption etc.) were estimated in the "sporting" and "athletic" groups. 2. In the 2 latter groups, distinguished by greater physical activity, the atypical enzyme activity pattern, remarkable by a low activity of LDH and high relative activities of GPDH and HK, as reported earlier in a sedentary group (Bass et al., 1975a), disappeared. The possibility of the atypical low LDH enzyme activity pattern as resulting from lack of bodily exertion is discussed. 3. The moderately trained "sporting" group distinguishes itself from the "sedentary" one mainly by a higher activity of LDH and by lower activities of GPDH and MDH. In the intensively trained "athletic" group, enzymes connected to aerobic oxidation (MDH, CS, HOADH) and GPDH also show higher activities than in the "sporting" group. The difference between the two more active groups is further borne out by a higher maximum oxygen uptake and carbon dioxide release of the well-trained "athletic" group. This difference of enzyme activity pattern may not be confined to the quadriceps femoris muscle.

Effect of protracted intermittent fasting on the activities of enzymes involved in energy metabolism, and on the concentrations of glycogen, protein and DNA in skeletal muscle of obese women

In the quadriceps femoris muscle of obese women the glycogen concentration was significantly lower than in the control group, while protein and DNA values showed no significant differences. After 37 days of intermittent fasting, which consisted of repeated 5-day fasts alternating with 3-day intervals on 500 KCal/day with 60 g protein, in a group of 21 obese women a significant decline of the hexokinase activity in skeletal muscle was found. Other enzymes: triosophosphate dehydrogenase, lactate dehydrogenase, glycerol-3-phosphate dehydrogenase, citrate synthase, malate dehydrogenase and hydroxyacyl-CoA dehydrogenase showed no significant changes. There was a significant fall in concentration of DNA and and glycogen, but the protein concentration did not change.

Activity of some enzymes of energy metabolism in striated muscle of obese subjects with respect to body composition

The effect of obesity on the activity of some enzymes of energy supplying metabolism was studied in male and female groups of different body weight, using tissue samples of m. quadriceps femoris obtained by a biopsy needle. Both obese males and females displayed a distinct tendency towards anaerobic metabolism (high lactate dehydrogenase activities). The assumption that cytoplasm has an increased capacity in the muscle of the obese for reduction syntheses is supported by the increased ratio of malate dehydrogenase to citrate synthase activities. Compared with controls, less activity of enzymes associated with fatty acid and glucose degradation (hexokinase, hydroxyacyl-CoA dehydrogenase, citrate synthase) was observed in obese males. In obese females the latter enzyme activities did not differ from those in the controls; however, lactate dehydrogenase and triosophosphate dehydrogenase activities were significantly higher. Significant inverse correlations between hexokinase and hydroxyacyl- CoA dehydrogenase activities, on the one hand, and indicators of body composition and body weight, on the other, were found in males. The female group did not display analogous significant relations between the enzymatic organization and indicators of body composition.

Metabolic changes in the quadriceps femoris muscle of obese people. Enzyme activity patterns of energy-supplying metabolism

1. In biopsy samples of the lateral part of m. quadriceps femoris of 49 obese and 14 lean persons the activities of the following enzymes were investigated: triosephosphate dehydrogenase (TPDH), glycerolphosphate: nad dehydrogenase (GPDH), lactate dehydrogenase (LDH), hexokinase (HK), malate: NAD dehydrogenase (MDH), citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase (HOADH). 2. The muscles of obese had an increased activity ratio of TPDH to CS and to HK, respectively, caused in muscles of female obese subjects by an increase of TPDH activity, in those of obese men rather by a decrease of CS and HK activities. 3. Cluster analysis brough to light the existence of three major groups. Group 1 (low activity-low LDH group), consisting of muscles of female obese subjects only, exhibited low activities of all enzymes investigated, that of LDH being so low as to possibly induce a serious deficiency of anerobic metabolism under working conditions. Group 2 (medium enzyme activity group) was characterized by medium enzyme activities, similar to that of lean controls (included in this group). This consisted of subjects of both sex. Group 3 (high enzyme activity group) consisted of obese of both sex. It was distinguished by high enzyme activities, especially of LDH. It is suggested that the groups of similar enzyme activity patterns might reflect different stages, types and/or genesis of obesity.

Renal collateral blood supply after acute unilateral renal artery occlusion

Preformed arterial collaterals are critical to renal parenchymal survival after acute total renal artery occlusion. This study was designed to delineate and quantify preformed collaterals and assess their response to vasodilators. A Swan-Ganz catheter induced a sudden, total occlusion of a renal artery sufficient to reduce distal arterial pressure to near zero and prevent perfusion through the renal artery. Arteriography assessed the effectiveness of the occlusion and delineated the collateral arterial pathways. Strontium, cerium-, and chromium-labeled microspheres measured renal blood flow and cardiac output 1, 60, and 120 minutes after occlusion. In two additional series of experiments either contralateral nephrectomy was performed 5 to 8 days before the study, or dibenzylene, dopamine, or glucagon were administered in an attempt to increase blood flow through the collaterals. Collateral renal blood flow was demonstrated in all dogs. Mean blood flow to the occluded kidneys ranged from 0.13 +/- 0.05 cm3/minute/g to 0.22 +/- 0.08 cm3/minute/g, about 5% of control values. Neither prior contralateral nephrectomy nor vasodilator agents increased the flow to the obstructed kidneys. In the dogs with intact contralateral kidneys, however, there was a progressive decrease in cardiac output during the experiment, which was not found in uninephrectomized animals. We concluded that preformed arterial channels are available to maintain a small, but probably critical level of perfusion following sudden total occlusion of the renal artery. Neither hypertrophy due to prior contralateral nephrectomy nor active vasodilators modify flow through the preformed channels. It is likely that total renal ischemia provides a maximal stimulus for vasodilatation. The pattern of hind limb collaterals differed strikingly from those of the kidney, with maintenance of a greater portion of a normal flow and rapid increase in flow within 1 hour after femoral artery occlusion. Thus, data concerning collateral circulation cannot be generalized from one vascular bed to another even in the same species.

M. Quadriceps femoris of man, a muscle with an unusual enzyme activity pattern of energy supplying metabolism in mammals

1. The following enzyme activities were estimated in needle-biopsy samples of the lateral part of the human quadriceps femoris muscle: triosephosphate dehydrogenase (TPDH), lactate dehydrogenase (LDH), NAD : glycerol-3-phosphate dehydrogenase (GPDH), hexokinase (HK), NAD: malate dehydrogenase (MDH), citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase. 2. Although the enzyme activities in muscles of women were lesser than in those of men, no difference was found in the calculated enzyme activity ratios. There is thus no sex-dependent metabolic type-differentiation in this muscle. 3. The human quadriceps femoris is a low-activity muscle, in comparison with muscles of homoiotherm laboratory animals. The enzyme activity ratio of TPDH to CS, characterizing the glycolytic pyruvate formation to aerobic oxidative capacities, shows this muscle to be of an intermediate type in this respect, similarly as the extensor digitorum longus of the rat. The relatively very high capacity of glucose phosphorylation (HK), the high aerobic regeneration of cytoplasmic dehydrogenated NAD (GPDH) and the very low anaerobic regeneration (LDH), show the unusually high proportion of carbohydrates (glucose) which can be broken down aerobically.

Biochemical and histochemical changes in energy supply enzyme pattern of muscles of the rat during old age

Senile muscles of the rat (28-36 months) show loss of overall activity of glycolytic and aerobic enzymes. However, there is a differential loss and shift of enzyme activity pattern in the three types of muscles. The extensor digitorum longus (EDL) and diaphragm show a decrease of ratios of glycolytic to aerobic-oxidative enzymes. This shift to a more oxidative type of metabolism is not observed in the soleus muscle. Decrease of enzyme activities is least marked in the diaphragm muscle. Biochemical analysis shows a trend to levelling out of metabolic differences between the different muscle types. This trend of 'dedifferentiation' is most marked when comparing EDL and soleus, least marked when comparing EDL and diaphragm muscle. The histochemical analysis shows a shift from the original mixed to a more uniform pattern of muscle fibres in the EDL and soleus muscle; this levelling-out of differences between enzymatic activities of different muscle fibres is not observed in the diaphragm muscle. Preferential atrophy and loss of ATPase activity in II muscle fibres in the soleus muscle and the occurrence of 'type grouping' are further characteristic features of senile muscle change. The findings show general (i.e. loss of enzyme activities) and differential trends of biochemical and histochemical enzyme changes in different types of muscles.