Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to compare the effects of two programs of endurance training, of equal duration and intensity, on bone development in female rats. Thirty-eight female Wistar rats were randomly assigned to one of three groups: run-trained (RUN), swim-trained (SWIM) or control (CON). The RUN group ran at a speed of 27 m/min up an 8 degrees incline. Swim trained animals swam with 2% of body weight attached to their tails. Training sessions were 2 h/day, 5 days/week and were conducted over a 10-week period. Hindlimb and forelimb muscles were removed upon sacrifice and analyzed for citrate synthase (CS) activity, liver (LG) and muscle (MG) glycogen. The parametrial fat pads were removed, digested with collagenase, and 2-deoxy-D-[3H]glucose uptake measured in isolated cells. Bone weight, length, diameter, ponderal index and bone mineral content (BMC) were measured in the femur and humerus of each animal. The LG, MG, fat cell volume, glucose uptake of the adipocyte and adrenal weight data indicate that the training response was identical. The CS activity of the muscles indicated that mechanical and recruitment patterns of the upper and lower body differ and could be responsible for bone development patterns found in this study. Exercise had a minimal effect on bone growth in the run-trained animals but did stimulate development in the swim-trained animals. The humerus of the SWIM was significantly (P < 0.05) heavier, wider and had a greater BMC when compared with those of the RUN and CON rats. The results of this study indicate that the muscular forces applied by the swim training protocol produced greater bone adaptations than the forces applied by a running protocol of equal duration and intensity.
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PMID:The effects of exercise mode, swimming vs. running, upon bone growth in the rapidly growing female rat. 134 May 16

1. A method is described for extracting separately mitochondrial and extramitochondrial enzymes from fat-cells prepared by collagenase digestion from rat epididymal fat-pads. The following distribution of enzymes has been observed (with the total activities of the enzymes as units/mg of fat-cell DNA at 25 degrees C given in parenthesis). Exclusively mitochondrial enzymes: glutamate dehydrogenase (1.8), NAD-isocitrate dehydrogenase (0.5), citrate synthase (5.2), pyruvate carboxylase (3.0); exclusively extramitochondrial enzymes: glucose 6-phosphate dehydrogenase (5.8), 6-phosphogluconate dehydrogenase (5.2), NADP-malate dehydrogenase (11.0), ATP-citrate lyase (5.1); enzymes present in both mitochondrial and extramitochondrial compartments: NADP-isocitrate dehydrogenase (3.7), NAD-malate dehydrogenase (330), aconitate hydratase (1.1), carnitine acetyltransferase (0.4), acetyl-CoA synthetase (1.0), aspartate aminotransferase (1.7), alanine aminotransferase (6.1). The mean DNA content of eight preparations of fat-cells was 109mug/g dry weight of cells. 2. Mitochondria showing respiratory control ratios of 3-6 with pyruvate, about 3 with succinate and P/O ratios of approaching 3 and 2 respectively have been isolated from fat-cells. From studies of rates of oxygen uptake and of swelling in iso-osmotic solutions of ammonium salts, it is concluded that fat-cell mitochondria are permeable to the monocarboxylic acids, pyruvate and acetate; that in the presence of phosphate they are permeable to malate and succinate and to a lesser extent oxaloacetate but not fumarate; and that in the presence of both malate and phosphate they are permeable to citrate, isocitrate and 2-oxoglutarate. In addition, isolated fat-cell mitochondria have been found to oxidize acetyl l-carnitine and, slowly, l-glycerol 3-phosphate. 3. It is concluded that the major means of transport of acetyl units into the cytoplasm for fatty acid synthesis is as citrate. Extensive transport as glutamate, 2-oxoglutarate and isocitrate, as acetate and as acetyl l-carnitine appears to be ruled out by the low activities of mitochondrial aconitate hydratase, mitochondrial acetyl-CoA hydrolyase and carnitine acetyltransferase respectively. Pathways whereby oxaloacetate generated in the cytoplasm during fatty acid synthesis by ATP-citrate lyase may be returned to mitochondria for further citrate synthesis are discussed. 4. It is also concluded that fat-cells contain pathways that will allow the excess of reducing power formed in the cytoplasm when adipose tissue is incubated in glucose and insulin to be transferred to mitochondria as l-glycerol 3-phosphate or malate. When adipose tissue is incubated in pyruvate alone, reducing power for fatty acid, l-glycerol 3-phosphate and lactate formation may be transferred to the cytoplasm as citrate and malate.
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PMID:The intracellular localization of enzymes in white-adipose-tissue fat-cells and permeability properties of fat-cell mitochondria. Transfer of acetyl units and reducing power between mitochondria and cytoplasm. 439 82

Endurance exercise training increases smooth muscle L-type Ca(2+) current density in both resistance and proximal coronary arteries of female miniature swine. The purpose of the present study was to determine 1) whether gender differences exist in coronary smooth muscle (CSM) L-type Ca(2+) current density and 2) whether endurance training in males would demonstrate a similar adaptive response as females. Proximal, conduit (approximately 1.0 mm), and resistance [~200 microm (internal diameter)] coronary arteries were obtained from sedentary and treadmill-trained swine of both sexes. CSM were isolated by enzymatic digestion (collagenase plus elastase), and voltage-gated Ca(2+)-channel current (I(Ca)) was determined by using whole cell voltage clamp during superfusion with 75 mM tetraethylammonium chloride and 10 mM BaCl(2). Current-voltage relationships were obtained at test potentials from -60 to 70 mV from a holding potential of -80 mV, and I(Ca) was normalized to cell capacitance (pA/pF). Endurance treadmill training resulted in similar increases in heart weight-to-body weight ratio, endurance time, and skeletal muscle citrate synthase activity in male and female swine. I(Ca) density was significantly greater in males compared with females in both conduit (-7.57 +/- 0.58 vs. -4.14 +/- 0.47 pA/pF) and resistance arteries (-11.25 +/- 0.74 vs. -6.49 +/- 0.87 pA/pF, respectively). In addition, voltage-dependent activation of I(Ca) in resistance arteries was shifted to more negative membrane potentials in males. Exercise training significantly increased I(Ca) density in both conduit and resistance arteries in females (-7.01 +/- 0.47 and -9.73 +/- 1.13 pA/pF, respectively) but had no effect in males (-8.61 +/- 0.50 and -12.04 +/- 1.07 pA/pF, respectively). Thus gender plays a significant role in determining both the magnitude and voltage dependence of I(Ca) in CSM and the adaptive response of I(Ca) to endurance training.
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PMID:Gender influences coronary L-type Ca(2+) current and adaptation to exercise training in miniature swine. 1171 11