5'-Aminolevulinate synthase activity is decreased in skeletal muscle of anemic rats

1992 ◽  
Vol 263 (2) ◽  
pp. C429-C435 ◽  
Author(s):  
L. A. McNabney ◽  
D. A. Essig
Keyword(s):  
Skeletal Muscle ◽  
Enzyme Activity ◽  
Citrate Synthase ◽  
Muscle Growth ◽  
Biosynthetic Enzyme ◽  
Deficient Diet ◽  
Aminolevulinate Synthase ◽  
Iron Deficient ◽  
Old Rats ◽  
Rate Limiting

Expression of the rate-limiting heme biosynthetic enzyme 5'-aminolevulinate synthase (ALAS) was investigated in skeletal muscle of 3-wk-old rats fed an iron-deficient diet. After 14 days, ALAS activity had declined 70% relative to control (2.1 +/- 0.2 vs. 0.6 +/- 0.1 nmol.h-1.g-1; P less than 0.005). Similar decreases were observed for blood hemoglobin (11.4 +/- 0.2 vs. 3.9 +/- 0.3 g/dl; P less than 0.005) and muscle cytochrome c (14.5 +/- 1.3 vs. 7.1 +/- 0.6 nmol/g; P less than 0.005). An iron-deficient diet decreased body and skeletal muscle growth by 15 (P less than 0.005) and 10% (P less than 0.05), respectively, whereas concentrations of protein, RNA, ALAS mRNA, and citrate synthase activity in muscle were not different from control. One mechanism by which heme biosynthesis may be slowed in muscle of young anemic rats is a decrease in ALAS activity. At a time when enzyme activity was decreased, ALAS mRNA expression was not affected by an iron-deficient diet, suggesting that steps after transcription of the ALAS gene may regulate the decrease in activity.

Induction of an increase in mitochondrial matrix enzymes in muscle of iron-deficient rats

1987 ◽  
Vol 253 (5) ◽  
pp. C639-C644 ◽  
Author(s):  
Y. Ohira ◽  
L. J. Cartier ◽  
M. Chen ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Iron Deficiency ◽  
Mitochondrial Biogenesis ◽  
Citrate Synthase ◽  
Weight Bearing ◽  
Mitochondrial Matrix ◽  
Vigorous Exercise ◽  
Deficient Diet ◽  
Coa Transferase ◽  
Iron Deficient

Young rats maintained on an iron-deficient diet developed severe anemia and had large decreases in the levels of the iron-containing flavoproteins and cytochromes of the mitochondrial respiratory chain in skeletal muscle. In contrast, the levels of a number of mitochondrial matrix marker enzymes, including citrate synthase, isocitrate dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase, 3-ketoacid-CoA transferase, and aspartate aminotransferase, increased in red skeletal muscle but not in white muscle. Phosphocreatine concentration was decreased and inorganic phosphate concentration was increased in soleus muscle frozen in situ. We hypothesize that the increase in mitochondrial matrix enzymes reflects a stimulus to mitochondrial biogenesis in posture-maintaining and weight-bearing red muscle fibers in severely iron-deficient rats. It is our working hypothesis that this stimulus to mitochondrial biogenesis arises from mild activity of the red fibers and is due to the same perturbation in cellular homeostasis that is normally caused by vigorous exercise or hypoxia. In iron deficiency, the stimulus to mitochondrial biogenesis can induce an increase in only those enzymes not prevented from increasing by iron deficiency, resulting in formation of mitochondria of grossly abnormal composition.

Physiological and biochemical correlates of increased work in trained iron-deficient rats

1988 ◽  
Vol 65 (1) ◽  
pp. 256-263 ◽  
Author(s):  
W. T. Willis ◽  
P. R. Dallman ◽  
G. A. Brooks
Keyword(s):  
Skeletal Muscle ◽  
Nadh Oxidase ◽  
Tca Cycle ◽  
Work Capacity ◽  
Oxidative Capacity ◽  
Oxidative Enzymes ◽  
Tca Cycle Enzymes ◽  
Iron Deficient ◽  
Old Rats ◽  
Physiological And Biochemical

We investigated physiological and biochemical factors associated with the improved work capacity of trained iron-deficient rats. Female 21-day-old rats were assigned to one of four groups, two dietary groups (50 and 6 ppm dietary iron) subdivided into two levels of activity (sedentary and treadmill trained). Iron deficiency decreased hemoglobin (61%), maximal O2 uptake. (VO2max) (40%), skeletal muscle mitochondrial oxidase activities (59-90%), and running endurance (94%). In contrast, activities of tricarboxylic acid (TCA) cycle enzymes in skeletal muscle were largely unaffected. Four weeks of mild training in iron-deficient rats resulted in improved blood lactate homeostasis during exercise and increased VO2max (15%), TCA cycle enzymes of skeletal muscle (27-58%) and heart (29%), and liver NADH oxidase (34%) but did not affect any of these parameters in the iron-sufficient animals. In iron-deficient rats training affected neither the blood hemoglobin level nor any measured iron-dependent enzyme pathway of skeletal muscle but substantially increased endurance (230%). We conclude that the training-induced increase in endurance in iron-deficient rats may be related to cardiovascular improvements, elevations in liver oxidative capacity, and increases in the activities of oxidative enzymes that do not contain iron in skeletal and cardiac muscle.

Muscle respiratory capacity and VO2 max in identically trained young and old rats

1987 ◽  
Vol 63 (1) ◽  
pp. 257-261 ◽  
Author(s):  
G. D. Cartee ◽  
R. P. Farrar
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Treadmill Running ◽  
Whole Body ◽  
Vo2 Max ◽  
Respiratory Enzymes ◽  
Respiratory Capacity ◽  
Palmitate Oxidation ◽  
Age Related ◽  
Old Rats

Old rats have a decreased hindlimb muscle respiratory capacity and whole-body maximal O2 consumption (VO2 max). The decline in spontaneous physical activity in old rats might contribute to these age-related changes. The magnitude of the age-related decline is not uniform in all skeletal muscle respiratory enzymes, and the decrease in palmitate oxidation is particularly great. This study was designed to determine if young and old rats subjected to the same exercise-training protocol would attain similar values for VO2 max and several markers of muscle respiratory capacity. Four- and 18-mo-old Fischer 344 rats underwent an identical 6-mo program of treadmill running. After training, both age groups had increased VO2 max above sedentary age-matched controls. However, the old trained rats had a lower VO2 max than identically trained young rats. In contrast to VO2 max, the two trained groups attained similar values for gastrocnemius citrate synthase, cytochrome oxidase, 3-hydroxyacyl-CoA dehydrogenase, palmitate oxidation, and total carnitine concentration. Thus, when the young and old rats performed an identical exercise protocol within the capacity of the old animals, differences in skeletal muscle respiratory capacity were eliminated. The dissimilarity in VO2 max between the identically trained groups was apparently caused by age-related differences in factors other than muscle respiratory capacity.

scholarly journals Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab

1971 ◽  
Vol 121 (3) ◽  
pp. 399-409 ◽  
Author(s):  
Hans W. Behrisch
Keyword(s):  
Skeletal Muscle ◽  
Enzyme Activity ◽  
Low Temperature ◽  
Temperature Sensitive ◽  
King Crab ◽  
Rate Limiting Step ◽  
Low Concentrations ◽  
Higher Temperature ◽  
Paralithodes Camtschatica ◽  
Rate Limiting

1. The properties of fructose diphosphatase from skeletal muscle of the Alaskan king-crab (Paralithodes camtschatica) were examined over the physiological temperature range of the animal. 2. King-crab muscle fructose diphosphatase is first activated by Na+ and NH4+ and is then partially inhibited by these cations at concentrations higher than 10mm at 0°, 8° and 15°C. Enzyme activity is stimulated by K+ at 0°C, but is curtailed at 8°C and 15°C, an effect that could render rate independent of temperature. 3. Affinity for substrate increases with decreasing temperature; below the temperature of acclimatization, Km for fructose 1,6-diphosphate increases, resulting in a complex U-shaped temperature–Km curve. 4. King-crab muscle fructose diphosphatase is inhibited by low concentrations of AMP. As with enzymes of other poikilotherms, inhibition by AMP is sensitive to temperature; the enzyme is least sensitive to inhibition by AMP near the temperature of acclimatization. 5. The affinity of fructose diphosphatase for fructose 1,6-diphosphate is enhanced by phosphoenolpyruvate, and this activation is temperature-sensitive; 0.5mm-phosphoenolpyruvate causes a sevenfold decrease in Km for fructose 1,6-diphosphate at 15°C but a 25-fold decrease at 0°C. 6. Phosphoenolpyruvate appears to decrease the affinity of king-crab muscle fructose diphosphatase for AMP at low temperature, whereas at the higher temperature it appears to enhance inhibition by AMP. Phosphoenolpyruvate was not observed to cause a reversal of inhibition of fructose diphosphatase activity by AMP. The identification of phosphoenolpyruvate as an activator of a rate-limiting step in gluconeogenesis permits the suggestion of a coupling of the controlling mechanisms of several steps in the glycolytic and gluconeogenic chains. 7. These findings suggest mechanisms for the maintenance and regulation of control of fructose diphosphatase activity in king-crab skeletal muscle at low temperature and under conditions that favour concomitant activity of phosphofructokinase.

Lack of effect of ageing on acetate oxidation in rat skeletal muscle during starvation: a (13)C NMR study

2000 ◽  
Vol 203 (6) ◽  
pp. 995-1001
Author(s):  
V. Mezzarobba ◽  
G. Bielicki ◽  
F.M. Jeffrey ◽  
M. Mignon ◽  
J.P. Renou ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Citrate Synthase ◽  
Acetate Oxidation ◽  
Rat Skeletal Muscle ◽  
Acetyl Coenzyme A ◽  
Nmr Study ◽  
Old Rats ◽  
C Nmr

Acetate oxidation was examined by (13)C nuclear magnetic resonance in skeletal muscle from adult and old rats. Rats fasted for 5 days were perfused with [2-(13)C]acetate over 2 h, and muscle extracts were analyzed for [(13)C]glutamate isotopomers. This study shows that approximately 80 % of acetyl-coenzyme A entering the tricarboxylic cycle was derived from substrate infusion in both adult and old rats, and that the flux through anaplerotic pathways was approximately 21 % of the flux through citrate synthase. These data demonstrate that skeletal muscle from adult and old rats oxidizes the same proportion of exogenous acetate.

Fiber type and citrate synthase activity in the human gastrocnemius and vastus lateralis with aging

1998 ◽  
Vol 85 (4) ◽  
pp. 1337-1341 ◽  
Author(s):  
Joseph A. Houmard ◽  
Melinda L. Weidner ◽  
Karen E. Gavigan ◽  
Gilian L. Tyndall ◽  
Matthew S. Hickey ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Enzyme Activity ◽  
Aging Process ◽  
Human Skeletal Muscle ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Maximal Oxygen Consumption ◽  
Muscle Group ◽  
Age Range

The purpose of this study was to determine whether enzymatic and histochemical characteristics of human skeletal muscle are altered with aging. Tissues from the vastus lateralis (VL) and gastrocnemius were analyzed for citrate synthase (CS) activity and fiber type in 55 sedentary men (age range 18–80 yr). In this population, CS activity in the gastrocnemius was negatively related to age ( r = −0.32, P < 0.05); there was no relationship in the VL. Treadmill-determined maximal oxygen consumption was positively related ( r = 0.40, P < 0.05) to CS in the gastrocnemius but not in the VL. CS activity in the gastrocnemius was 24% lower in the oldest (≥60 yr, n = 10) vs. the youngest (≤30 yr; n = 12) men; there was no change in CS activity in the VL with aging. No changes in fiber type were evident with age in either muscle. These data suggest a reduction in oxidative enzyme activity in human skeletal muscle with the aging process; this relationship may be muscle-group specific.

Selected Contribution: Skeletal muscle capillarity and enzyme activity in rats selectively bred for running endurance

2003 ◽  
Vol 94 (4) ◽  
pp. 1682-1688 ◽  
Author(s):  
Richard A. Howlett ◽  
Norberto C. Gonzalez ◽  
Harrieth E. Wagner ◽  
Zhenxing Fu ◽  
Steven L. Britton ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Enzyme Activity ◽  
Citrate Synthase ◽  
Capillary Density ◽  
Medial Gastrocnemius ◽  
Endurance Running ◽  
Muscle Enzymes ◽  
Fiber Number ◽  
The Difference ◽  
Seven Generations

To attempt to explain the difference in intrinsic (untrained) endurance running capacity in rats selectively bred over seven generations for either low (LCR) or high running capacity (HCR), the relationship among skeletal muscle capillarity, fiber composition, enzyme activity, and O2 transport was studied. Ten females from each group [body wt: 228 g (HCR), 247 g (LCR); P= 0.03] were studied at 25 wk of age. Peak normoxic maximum O2 consumption and muscle O2 conductance were previously reported to be 12 and 33% higher, respectively, in HCR, despite similar ventilation, arterial O2 saturation, and a cardiac output that was <10% greater in HCR compared with LCR. Total capillary and fiber number in the medial gastrocnemius were similar in HCR and LCR, but, because fiber area was 37% lower in HCR, the number of capillaries per unit area (or mass) of muscle was higher in HCR by 32% ( P < 0.001). A positive correlation ( r = 0.92) was seen between capillary density and muscle O2 conductance. Skeletal muscle enzymes citrate synthase and β-hydroxyacyl-CoA dehydrogenase were both ∼40% higher ( P < 0.001) in HCR (12.4 ± 0.7 vs. 8.7 ± 0.4 and 3.4 ± 0.2 vs. 2.4 ± 0.2 mmol · kg−1 · min−1, respectively), whereas phosphofructokinase was significantly ( P = 0.02) lower in HCR (27.8 ± 1.2 vs. 35.2 ± 2.5 mmol · kg−1 · min−1) and hexokinase was the same (0.65 ± 0.04 vs. 0.65 ± 0.03 mmol · kg−1 · min−1). Resting muscle ATP, phosphocreatine, and glycogen contents were not different between groups. Taken together, these data suggest that, in rats selectively bred for high-endurance exercise capacity, most of the adaptations for improved O2 utilization occur peripherally in the skeletal muscles and not in differences at the level of the heart or lung.

Regulation of 5'-aminolevulinate synthase activity in overloaded skeletal muscle

1990 ◽  
Vol 259 (2) ◽  
pp. C310-C314 ◽  
Author(s):  
D. A. Essig ◽  
J. M. Kennedy ◽  
L. A. McNabney
Keyword(s):  
Skeletal Muscle ◽  
Enzyme Activity ◽  
Cytochrome Oxidase ◽  
Weight Bearing ◽  
Mitochondrial Enzyme ◽  
Total Rna ◽  
Aminolevulinate Synthase ◽  
Initial Rise ◽  
Mrna Content ◽  
Chicken Skeletal Muscle

The regulation of the mitochondrial enzyme 5'-aminolevulinate synthase (ALV synthase) activity during chronic weight-bearing activity (overload) in chicken skeletal muscle was investigated. Maximal enzyme activity was increased 2.5- and 4.0-fold after 3 and 7 days of overload. The content of ALV synthase mRNA (ng/mg total RNA) was not changed after 3 days but increased (20%; P less than 0.05) after 7 days of overload. Normalizing the content of ALV synthase mRNA relative to the increase in total RNA indicated that ALV synthase mRNA increased by 1.6- and 2.0-fold at 3 and 7 days, respectively. On this basis, the increase in enzyme activity per gram protein exceeded the increase in mRNA content per gram protein by 60-70%. During overload, the activity of cytochrome oxidase was unchanged after 3 days but increased by 1.5-fold (P less than 0.05) after 7 days of overload. The data indicate that 1) the initial rise in ALV synthase mRNA and activity due to overload occurs in the absence of a prior change in the level of cytochrome oxidase, an enzyme that requires heme for its assembly, and 2) induction of ALV synthase activity is regulated largely by processes at the translational or posttranslational steps.

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

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