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Biomedical subjects

J Teisinger

Publications and source records attributed to J Teisinger.

At least 55 records · Page 3Linked to original sources
PubMed1982

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↗
PubMed1982

Activities of muscle energy supplying enzymes after 5 days complete fasting in young men.

The effect of 5 days' complete fasting on the activity of 7 enzymes of energy supplying metabolism was studied in the vastus lateralis muscles of 9 healthy male volunteers. There was a significant decrease of lactate dehydrogenase (by 66%), triosephosphate dehydrogenase (by 61%), malate:NAD dehydrogenase (by 48%), hexokinase (by 40%), 3-hydroxyacyl-CoA-dehydrogenase (by 40%), triosephosphate dehydrogenase/3-hydroxyacyl-CoA-dehydrogenase (by 35%), citrate synthase (by 33%). Glycerolphosphate:NAD dehydrogenase activity did not decrease significantly. These findings suggest a) that utilization of the major energy substrates decreases; b) that the decrease mainly concerns the catabolism of carbohydrates, that of fatty acids to a lesser extent; c) that the decreased capacity of carbohydrate catabolism is partly compensated for by the predominance of the more economic aerobic-oxidative pathway; d) that the reducing equivalents formed in the cytosol may be transported via the glycerolphosphate shuttle into the respiratory chain to a greater extent, so that a greater portion is not lost by the reduction of pyruvate to lactate.

Adult↗
PubMed1981

Effects of sleep deprivation on the activity of selected metabolic enzymes in skeletal muscle.

The effect of 120-h sleep deprivation on the activity of selected enzymes of energy metabolism in skeletal muscle was studied in seven healthy volunteers. The results showed a significant decrease in the activity of malate dehydrogenase, citrate synthase, glycerol-3-phosphate dehydrogenase and lactate dehydrogenase. Triosephosphate dehydrogenase, hexokinase, and hydroxyacyl-CoA-dehydrogenase activities showed an insignificant decrease. The findings are indicative of (1) decreased aerobic oxidation capacity; (2) reduced function of reducing-equivalent carriers from cytosol across the mitochondrial membrane; (3) relative accentuation of the non-aerobic glycolytic pathway; (4) a prediabetic type of muscle metabolism.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1981

The effect of vanadate on the electrogenic Na+/K+ pump, intracellular Na+ concentration and electrophysiological characteristics of mouse skeletal muscle fibre.

The present study reports a discrepancy between the effects of vanadate on the membrane Na+-K+-ATPase and the Na+/K+ pump of the skeletal muscle. Vanadate in concentration 4 X 10(-6) mol/l which is necessary to block the enzyme Na+-K+-ATPase activity of membrane fractions failed to inhibit the electrogenic Na+/K+ pump of intact muscle cells. The effect of vanadate on the electrophysiological parameters of the muscle fibre membrane required much higher vanadate levels, but again, Na+/K+ pump was still active. Vanadate in concentrations 4 X 10(-4) and 4 X 10(-5) mol/l depolarized the membrane potential and decreased the membrane resistance [apparently in consequence of enhanced passive membrane permeability for Na+ ions]. Action potentials and the electrical excitability of the muscle fibre membrane were reduced by these vanadate concentrations.

Action Potentials↗
PubMed1981

Activity of some enzymes of energy metabolism during denervation and reflex atrophy in rat slow and fast muscles.

The loss of muscle weight in the soleus (SOL) and extensor digitorum longus (EDL) muscles was compared after denervation and in the course of reflex muscle atrophy induced by unilateral fracture of metatarsal bones of the paw and local injection of 0.02 ml turpentine oil subcutaneously. This so-called reflex atrophy is significantly greater after 3 days than that after denervation. Seven days after the nociceptive stimulus, reflex and denervation atrophy are grossly similar in both muscles. This also applies in case that the nociceptive stimulus had been repeated on the third day. The EDL:SOL enzyme activities of energy supply metabolism reflect the differences between a glycolytic-aerobic (EDL) and predominantly aerobic type (SOL) of muscle. No consistent changes were found in either type of atrophy after 3 days. In 7 days' denervation, the activity of hydroxyacetyl-CoA-dehydrogenase (HOADH) and citrate synthase (CS) was decreased in the SOL, while glycerolphosphate:NAD dehydrogenase (GPDH) was enhanced. In the EDL, the activity of triosephosphate dehydrogenase (TPDH), GPDH, malate dehydrogenase (MDH), CS and HOADH was decreased. Acid phosphatase (AcP) was greatly increased in both muscles. Seven days after application of the nociceptive stimulus, all enzyme activities were altered in a grossly analogous manner as after denervation.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1980

A specific enzyme is not necessary for vanadate-induced oxidation of NADH.

It has recently been found that ortho- or metavanadate can effectively block (Na+ + K+)ATPase and that it loses its blocking potency when reduced to the vanadyl (VO2+) ion. The question arose whether vanadate could be involved (reduced) in an NAD-linked enzymatic redox system of the cell. Here we have studied the effect of vanadate on malate dehydrogenase (MDH, EC1.1.1.37) catalysed oxidation of NADH during the formation of malate from oxalacetate in vitro. The MDH reaction was accelerated by vanadate, but we found thatr vanadate does not require the presence of any specific enzyme or substrate to mediate NADH oxidation.

Buffers↗
PubMed1980

Effect of cycloheximide administered to rats in early postnatal life: prolonged inhibition of DNA synthesis in the developing brain.

Administration of cycloheximide in a single dose of 0.6 mg/kg to 7-day-old rats was used to induce short-term inhibition of protein synthesis at the period of brain 'growth spurt'. Measurement of the rate of [14C]lysine incorporation indicated that the initial inhibition of protein synthesis in the brain (by 75%) was released within about 12 h. The normal rate of protein synthesis was attained by 48 h after cycloheximide administration; there was no sign of protein synthesis stimulation. The estimation of [14C]thymidine incorporation into brain DNA showed that inhibition of DNA synthesis was greater and longer lasting in the forebrain and olfactory bulbs (by about 80%) than in the cerebellum (by about 40%). Similar differential inhibition of thymidine kinase activity was observed in the olfactory bulbs (by 75%) and cerebellum (by 30%) at 24 h after cycloheximide, suggesting that the formation of [14C]thymidine nucleotides may have been impaired. However, a retardation of DNA accumulation was found in the forebrain and cerebellum at 72 h after cycloheximide. Thus, the short-term inhibition of protein synthesis produced prolonged inhibition of DNA synthesis and altered cell proliferation in the developing brain.

Animals↗
PubMed1980

Effect of temperature and ouabain on th Na+--K+ activated membrane ATPase and electrogenic ionic pump of the golden hamster and mouse diaphragm.

The activity of membrane Na+--K+-ATPase and electrogenic ionic pump was estimated by biochemical and electrophysiological techniques on diaphragm muscles of mouse and non-hibernating golden hamster between 5 degrees C to 37 degrees C. The electrogenic capacity of ionic pump (measured as maximum hyperpolarization after adding 5 nmol/l K+ to Na+-enriched muscle) was highest at 37 degrees C for the mouse and between 25--30 degrees C for the golden hamster. At lower temperatures (15 degrees C--5 degrees C), the hyperpolarization after adding K+ reversed to depolarization between 15 degrees C and 10 degrees C in the case of the mouse. In the hamster, the slight hyperpolarization persisted even at 5 degrees C. With decreasing temperature, the activity of membrane ATPase of mouse and hamster membrane fraction decreased in both cases to the same extent between 37--25 degrees C. Within the temperature range between 10 degrees C and 5 degrees C the activity of this enzyme of hamster preparations was about 2.4 times higher than in the case of the mouse. In the mouse Na+-enriched diaphragm, ouabain (10(-4) mol/l) decreased the resting membrane potential (RMP) in a K+-free solution at 20 degrees C by about 5 mV, but in the golden hamster preparation, ouabain in the same concentration increased RMP of Na+-enriched diaphragm fibres by more than 5 mV. The activity of membrane ATPase of hamsters was increased by 10(-4) mol/l ouabain more than 2.5 times in a K+-free reaction medium, whereas in the case of the mouse no change of enzyme activity was observed. This indicates that ouabain can be substituted for potassium as an activator of membrane ATPase in the sarcolemma of golden hamster muscle fibres.

Animals↗
PubMed1980

Postnatal changes of some enzymatic activities of energy supplying metabolism in the cortex, inner and outer medulla of the rat kidney.

1. In rat kidney cortex, outer and inner medulla the development of activities of seven enzymes was investigated during postnatal ontogeny (10, 20, 30, 60 and 90 days of age). The enzymes were selected in such a manner, as to characterize most of the main metabolic pathways of energy supplying metabolism: hexokinase (glucose phosphorylation, HK), glycerol-3-phosphate dehydrogenase (glycerolphosphate metabolism or shunt, GPDH), triose phosphate dehydrogenase (glycolytic carbohydrate breakdown, TPDH), lactate dehydrogenase (lactate metabolism, LDH), citrate synthase (tricarboxylic acid cycle, aerobic metabolism, CS), malate NAD dehydrogenase (tricarboxylic acid cycle, intra-extra mitochondrial hydrogen transport, MDH) and 3-hydroxyacyl-CoA-dehydrogenase (fatty acid catabolism, HOADH). 2. The renal cortex already differs metabolically from the medullar structures on the 10th day of life. It displays a high activity of aerobic breakdown of both fatty acids and carbohydrates. Its metabolic capacity further increases up to the 30th day of life. 3. The outer medullar structure is not grossly different from the inner medulla on the 10th day of life. Further it differentiates into a highly aerobic tissue mainly able to utilize carbohydrates. It can, however, to some extent, also utilize fatty acids aerobically and produce lactate from carbohydrates anaerobically. 4. The inner medullar structure is best equipped to utilize carbohydrates by anaerobic glycolysis, forming lactate. This feature is already pronounced on the 10th day of life, its capacity increases to some extent during postnatal development, being highest between the 10th and the 60th day of life.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1979

Activation of membrane Na+/K+-ATPase of mouse skeletal muscle by acetylcholine and its inhibition by alpha-bungarotoxin, curare and atropine.

The effect of acetylcholine and of three cholinolytic compounds (alpha-bungarotoxin, curare and atropine) on electrogenic Na+/K+ pump and activity of the membrane Na+/K+-ATPase of mouse skeletal muscles was studied. It was found that acetylcholine potentiated both the muscle electrogenic ionic pump and the Na+/K+-ATPase activity of crude membrane fractions. The cholinolytic drugs had inhibitory effects on both parameters, with the exception of curare which was ineffective in blocking the electrogenic ionic pump.

Acetylcholine↗
PubMed1979

Effects of ischaemia on enzyme-activities in the soleus muscle of the rat.

1. The changes with the time of the activities of some energy-supplying enzymes and of the hydrolytic enzyme, acid phosphatase, were studied over 2 weeks of complete ischaemia, produced in the rat soleus muscle by section of the abdominal aorta and terminal devascularization, leaving nerve and tendon intact. 2. Activities of glycolytic enzymes, oxidative enzymes, hexokinase and acid phosphatase are affected in a different manner. Activities of the glycolytic enzymes, lactate dehydrogenase, triosephosphate dehydrogenase and glycerolphosphate dehydrogenase, are lowest on the 1st day and increase thereafter. The first two reach the control values again on the 4th and 14th day, respectively, while glycerolphosphate dehydrogenase reaches about 50% of the control value on the 14th day. The maximum decrease in activity of the oxidative enzymes, citrate synthase, beta-hydroxyacyl-CoA-dehydrogenase and malate dehydrogenase occurs later (4th day); thereafter their activity returns slowly to control values, but does not reach them even on the 14th day. Hexokinase activity is slightly decreased on the 1st day; then it increased and reached on the 7th day twice the control value. Thus on the 1st day the activity of the enzymes of aerobic metabolism prevail, and on the 4th day those of anaerobic carbohydrate (glucose) metabolism; the recovery of enzyme activity of aerobic oxidation occurs later. 3. Acid phosphatase activity increased from the 2nd day onwards, reaching up to 3 times the control value on the 4th day and still twice that value on the 14th day. This agrees well with the histochemical picture of acid phosphatase. 4. Histochemical changes of alkaline phosphatase activity reveal destruction of capillary endothelial cells during the first few days after operation and their later proliferation from the periphery, correlating with the loss and recovery of oxidative enzyme activity.

3-Hydroxyacyl CoA Dehydrogenases↗