Functional and metabolic consequences of skeletal muscle remodeling in hypothyroidism

1991 ◽  
Vol 260 (2) ◽  
pp. E272-E279 ◽  
Author(s):  
R. M. McAllister ◽  
R. W. Ogilvie ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Control Group ◽  
Type I ◽  
Tetanic Contraction ◽  
Plantaris Muscle ◽  
Tension Development ◽  
Fiber Area ◽  
And Control ◽  
Muscle Remodeling

Functional and metabolic responses of hypothyroid skeletal muscle were evaluated during steady-state isometric contraction conditions, using an isolated perfused rat hindlimb preparation. Treating rats with propylthiouracil (PTU) for 4-5 mo resulted in a 55% decrease (P less than 0.001) in citrate synthase activity in plantaris muscle and phenotypic remodeling of the plantaris, evident by a threefold increase in type I fiber area and a 13% decrease in type II fiber area. Perfusion of PTU (n = 9) and control (n = 9) rat hindlimbs of similar size, with similar inflow (approximately 10 ml/min) and oxygen content (approximately 20 g/100 ml), resulted in similar oxygen deliveries to the contracting muscles (PTU 11.4 +/- 0.58, control 9.54 +/- 0.75 mumol.min-1.g-1; P greater than 0.05). Ten-minute tetanic contraction (100 ms at 100 Hz) periods at 4, 8, 15, 30, and 45 tetani/min were elicited in consecutive ascending order. Oxygen consumption (VO2) was lower in the PTU group at all contraction frequencies (P less than 0.005), with a decrease in peak VO2 of 44% (PTU 3.01 +/- 0.29, control 5.35 +/- 0.42 mumol.min-1.g-1; P less than 0.001). Oxygen extraction by the PTU muscle was only approximately 25% of that delivered. Developed tension was initially less (15%; P less than 0.05) in the PTU group but declined in a similar manner, as a percent of initial, to that of the control group. The slightly lower absolute tension development of the PTU muscle could not account for the large reduction in VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle fiber regeneration in nerve-intact and free skeletal muscle autografts in cats

1984 ◽  
Vol 246 (1) ◽  
pp. C96-C105 ◽  
Author(s):  
L. C. Maxwell
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Extensor Digitorum Longus ◽  
Contractile Properties ◽  
Type I ◽  
Tension Development ◽  
Fiber Area ◽  
Adult Cats ◽  
Type I Fibers ◽  
Muscle Fiber Regeneration

Extensor digitorum longus (EDL) muscles of adult cats were transplanted as free autografts (FRA) with the nerve severed or as nerve-intact autografts (NIA) with the nerve retained. Histochemical and contractile properties of NIA and FRA were analyzed at selected times from 1 to 14 wk after surgery. Regeneration was qualitatively similar in NIA and FRA. Regenerating fibers were observed in both NIA and FRA within 2 wk. After 14 wk there were fewer type I fibers in both NIA and FRA than in control EDL muscles. Capillarity was greater in NIA than FRA, but both types of autografts had significantly reduced capillarity relative to control muscles. Mean fiber area, muscle mass, and absolute tension development were greater in NIA than FRA but did not reach control muscle values. Muscle mass, mean fiber area, and contractile properties, but not the proportion of type I fibers, develop toward control values more quickly in autografts with the nerve left intact.

scholarly journals Atorvastatin impairs liver mitochondrial function in obese Göttingen Minipigs but heart and skeletal muscle are not affected

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liselotte Bruun Christiansen ◽  
Tine Lovsø Dohlmann ◽  
Trine Pagh Ludvigsen ◽  
Ewa Parfieniuk ◽  
Michal Ciborowski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Function ◽  
Citrate Synthase ◽  
Obese Group ◽  
Control Group ◽  
Dependent Manner ◽  
Respiratory Capacity ◽  
Protein Carbonyl Content ◽  
Functional Changes ◽  
Mitochondrial Respiratory

AbstractStatins lower the risk of cardiovascular events but have been associated with mitochondrial functional changes in a tissue-dependent manner. We investigated tissue-specific modifications of mitochondrial function in liver, heart and skeletal muscle mediated by chronic statin therapy in a Göttingen Minipig model. We hypothesized that statins enhance the mitochondrial function in heart but impair skeletal muscle and liver mitochondria. Mitochondrial respiratory capacities, citrate synthase activity, coenzyme Q10 concentrations and protein carbonyl content (PCC) were analyzed in samples of liver, heart and skeletal muscle from three groups of Göttingen Minipigs: a lean control group (CON, n = 6), an obese group (HFD, n = 7) and an obese group treated with atorvastatin for 28 weeks (HFD + ATO, n = 7). Atorvastatin concentrations were analyzed in each of the three tissues and in plasma from the Göttingen Minipigs. In treated minipigs, atorvastatin was detected in the liver and in plasma. A significant reduction in complex I + II-supported mitochondrial respiratory capacity was seen in liver of HFD + ATO compared to HFD (P = 0.022). Opposite directed but insignificant modifications of mitochondrial respiratory capacity were seen in heart versus skeletal muscle in HFD + ATO compared to the HFD group. In heart muscle, the HFD + ATO had significantly higher PCC compared to the HFD group (P = 0.0323). In the HFD group relative to CON, liver mitochondrial respiration decreased whereas in skeletal muscle, respiration increased but these changes were insignificant when normalizing for mitochondrial content. Oral atorvastatin treatment in Göttingen Minipigs is associated with a reduced mitochondrial respiratory capacity in the liver that may be linked to increased content of atorvastatin in this organ.

T3 increases mitochondrial ATP production in oxidative muscle despite increased expression of UCP2 and -3

2001 ◽  
Vol 280 (5) ◽  
pp. E761-E769 ◽  
Author(s):  
Kevin R. Short ◽  
Jonas Nygren ◽  
Rocco Barazzoni ◽  
James Levine ◽  
K. Sreekumaran Nair
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Atp Synthesis ◽  
Nutrient Flux ◽  
Oxidative Enzymes ◽  
Mrna Levels ◽  
Plantaris Muscle ◽  
Atp Production ◽  
Protein Levels ◽  
Different Types

Triiodothyronine (T3) increases O2 and nutrient flux through mitochondria (Mito) of many tissues, but it is unclear whether ATP synthesis is increased, particularly in different types of skeletal muscle, because variable changes in uncoupling proteins (UCP) and enzymes have been reported. Thus Mito ATP production was measured in oxidative and glycolytic muscles, as well as in liver and heart, in rats administered T3 for 14 days. Relative to saline-treated controls, T3 rats had 80, 168, and 62% higher ATP production in soleus muscle, liver, and heart, respectively, as well as higher activities of citrate synthase (CS; 63, 90, 25%) and cytochrome c oxidase (COX; 119, 225, 52%) in the same tissues (all P < 0.01). In plantaris muscle of T3 rats, CS was only slightly higher (17%, P < 0.05) than in controls, and ATP production and COX were unaffected. mRNA levels of COX I and III were 33 and 47% higher in soleus of T3 rats ( P < 0.01), but there were no differences in plantaris. In contrast, UCP2 and -3 mRNAs were 2.5- to 14-fold higher, and protein levels were 3- to 10-fold higher in both plantaris and soleus of the T3 group. We conclude that T3 increases oxidative enzymes and Mito ATP production and Mito-encoded transcripts in oxidative but not glycolytic rodent tissues. Despite large increases in UCP expression, ATP production was enhanced in oxidative tissues and maintained in glycolytic muscle of hyperthyroid rats.

scholarly journals Intermuscular Fat Content in Young Chinese Men With Newly Diagnosed Type 2 Diabetes: Based on MR mDIXON-Quant Quantitative Technique

2021 ◽  
Vol 12 ◽  
Author(s):  
Fuyao Yu ◽  
Bing He ◽  
Li Chen ◽  
Fengzhe Wang ◽  
Haidong Zhu ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Fat Content ◽  
Control Group ◽  
Diabetic Patients ◽  
Diabetes Group ◽  
Control Subjects ◽  
Intermuscular Fat ◽  
And Control

ObjectiveSkeletal muscle fat content is one of the important contributors to insulin resistance (IR), but its diagnostic value remains unknown, especially in the Chinese population. Therefore, we aimed to analyze differences in skeletal muscle fat content and various functional MRI parameters between diabetic patients and control subjects to evaluate the early indicators of diabetes. In addition, we aimed to investigate the associations among skeletal muscle fat content, magnetic resonance parameters of skeletal muscle function and IR in type 2 diabetic patients and control subjects.MethodsWe enrolled 12 patients (age:29-38 years, BMI: 25-28 kg/m2) who were newly diagnosed with type 2 diabetes (intravenous plasma glucose concentration≥11.1mmol/l or fasting blood glucose concentration≥7.0mmol/l) together with 12 control subjects as the control group (age: 26-33 years, BMI: 21-28 kg/m2). Fasting blood samples were collected for the measurement of glucose, insulin, 2-hour postprandial blood glucose (PBG2h), and glycated hemoglobin (HbAlc). The magnetic resonance scan of the lower extremity and abdomen was performed, which can evaluate visceral fat content as well as skeletal muscle metabolism and function through transverse relaxation times (T2), fraction anisotropy (FA) and apparent diffusion coefficient (ADC) values.ResultsWe found a significant difference in intermuscular fat (IMAT) between the diabetes group and the control group (p&lt;0.05), the ratio of IMAT in thigh muscles of diabetes group was higher than that of control group. In the entire cohort, IMAT was positively correlated with HOMA-IR, HbAlc, T2, and FA, and the T2 value was correlated with HOMA-IR, PBG2h and HbAlc (p&lt;0.05). There were also significant differences in T2 and FA values between the diabetes group and the control group (p&lt;0.05). According to the ROC, assuming 8.85% of IMAT as the cutoff value, the sensitivity and specificity of IMAT were 100% and 83.3%, respectively. Assuming 39.25ms as the cutoff value, the sensitivity and specificity of T2 value were 66.7% and 91.7%, respectively. All the statistical analyses were adjusted for age, BMI and visceral fat content.ConclusionDeposition of IMAT in skeletal muscles seems to be an important determinant for IR in type 2 diabetes. The skeletal muscle IMAT value greater than 8.85% and the T2 value greater than 39.25ms are suggestive of IR.

scholarly journals PO-055 Changes of trace elements in skeletal muscle and serum of rats after exercise-induced injury

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Jingyun Liu ◽  
Qun Zuo
Keyword(s):  
Skeletal Muscle ◽  
Trace Elements ◽  
Nitric Acid ◽  
Vena Cava ◽  
The Body ◽  
Emission Spectrometry ◽  
Control Group ◽  
Exercise Induced ◽  
And Control ◽  
Cu And Zn

Objective This study is to investigate the changes of trace elements (Cu, Fe, Zn, Se, Mg) in serum and skeletal muscle of rats after skeletal muscle injury induced by downhill running, and to find out the change regularity of trace elements in the body after exercise injury. To provide experimental basis for how to use trace elements supplements reasonably. Methods Fifty-four healthy male Sprague-Dawley rats aged 8 weeks were randomly divided into two groups: control group (C, N=6) and exercise group (E, N=48, include: 0 h group, 6 h group, 12 h group, 24 h group, 48 h group, 72 h group, 1- week group and 2- week group). The rats in exercise groups run down a 16°incline at 16m/min for 90 minutes. At the end of the exercise, the rats were killed at 0 h, 6 h, 12 h, 24 h, 48 h, 72 h, 1 week and 2 weeks, respectively. The serum was got from the inferior vena cava blood and diluted by 1% nitric acid. The muscle was got from the right side of the rat's sural which were digested by concentrated nitric acid and 30% hydrogen peroxide in 75℃water bath for 20mins. The content of trace elements in muscle and serum were measured by inductively coupled plasma atomic emission spectrometry (ICP-MS). All the data are analyzed and processed by SPSS22.0 statistical software. Results (1) The contents of trace elements in serum showed: Cu, Zn, Mg, Se decreased immediately after exercise, but the Cu still increased to reach a peak at 24h after decreasing, and after 2 weeks the content of Cu was slightly lower than pre-exercise level. However, the content of Zn did not elevate again, it continued declined to the lowest at 24h which was significantly lower than control group (P < 0.05). And after 2 weeks, Zn did not return to the pre-exercise level. The changes of Mg, Se in serum was not statistically significant. There is no difference between 0h and control groups in content of Fe, after that Fe decreased continually and appeared the least value at 24h, the differences between immediate group and control group were statistically significant (P < 0.05). Fe returned to the pre-exercise level after 2 weeks. (2) The contents of trace elements in muscle showed: Most of trace elements increased to the maximum level at 6 h, after that Mg, Fe, Cu decreased to the lowest value at 72 h which were significant lower than 0h group or 6h group (P < 0. 05). ALL the trace elements were lower than pre-exercise level. There was no statistical difference in the content of Se in muscle. Conclusions (1) The different changes of trace elements in skeletal muscle and serum after exercise injury may be due to the redistribution of trace elements caused by the body adaptability. (2) The most obviously changes of trace element in serum and muscle are Cu and Zn. Both of them did not return to the pre-exercise level after 2 weeks, it suggests that the supplement include Cu and Zn may play an important role in recovering after exercise-induced injury.

scholarly journals Implications of Aerobic Exercises and Walking Parallel to Diabetes Medications on Diabetic Sportspersons

2021 ◽  
pp. 197-204
Author(s):  
Fehmida Ayub ◽  
Abida Naseer ◽  
Saeed Javed ◽  
Adnan Asghar ◽  
Abd Rahim Mohd Shariff ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Blood Glucose Control ◽  
Daily Basis ◽  
Control Group ◽  
Type I ◽  
Type Ii ◽  
Glucose Levels ◽  
Spare Time ◽  
And Control ◽  
Experimental Group

Objective: Diabetes have a central contribution with type I or type II towards the healthy lifestyles of sportspersons. Aerobic exercise and daily walking stay them fit and control their glucose levels in their bloodstream. The aim of this study was to find out the effects of aerobic exercises and walk on the sportspersons of type I and II diabetes. Methodology: The existing research has experimental design itself wherein pre-tests and post-tests were employed to make sure the novelty of results. The data was collected from the diabetic sportspersons dividing them equally into control group (N-20) and experimental group (N-20). Both groups had type I (N-20) and type II (N-20) diabetic individuals. Aerobic exercise and walk protocol was applied for six weeks on experimental group, whereas, control group continued their routine activities. Afterwards, the data was collected through pre and post treatments and edited into SPSS (v-26). The collected data was analyzed through descriptive statistics using frequencies and percentages, whereas, T-test was applied to make the differences of pre and post treatments. Results: The findings has shown that aerobic exercises and walk decrease the higher levels of glucose in blood and enable to stable glycemic balance, weight loss maintenance, decrease insulin resistance, blood pressure decrease, and blood glucose control. Conclusion: The prominent differences were observed between control and experimental groups either type I or type II. It was concluded that the sportspersons may reduce the excessive glucose engaging in aerobic exercises and walk on daily basis rather than using medications. They should spend their happy lives and get rid of medications and insulin through spending their spare time using light exercises and maintain their glucose levels in blood as well.

scholarly journals Losartan has no additive effect on the response to heavy-resistance exercise in human elderly skeletal muscle

2018 ◽  
Vol 125 (5) ◽  
pp. 1536-1554 ◽  
Author(s):  
Mette Flindt Heisterberg ◽  
Jesper L. Andersen ◽  
Peter Schjerling ◽  
Alberte Lund ◽  
Simone Dalskov ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Angiotensin Ii ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Satellite Cells ◽  
Type I ◽  
Elderly Men ◽  
Fiber Area ◽  
Heavy Resistance Exercise

Our purpose here was to investigate the potential of blocking the angiotensin II type I receptor (AT1R) on the hypertrophy response of elderly human skeletal muscle to 4 mo of heavy-resistance exercise training. Fifty-eight healthy elderly men (+65 yr) were randomized into three groups, consuming either AT1R blocker (losartan, 100 mg/day) or placebo for 4 mo. Two groups performed resistance training (RT) and were treated with either losartan or placebo, and one group did not train but was treated with losartan. Quadriceps muscle biopsies, MR scans, and strength tests were performed at baseline and after 8 and 16 wk. Biopsies were sectioned for immunohistochemistry to determine the number of satellite cells, capillaries, fiber type distribution, and fiber area. Gene expression levels of myostatin, connective tissue, and myogenic signaling pathways were determined by real-time RT-PCR. Four months of heavy-resistance training led in both training groups to expected improvements in quadriceps (∼3–4%) and vastus lateralis (∼5–6%), cross-sectional area, and type II fiber area (∼10–18%), as well as dynamic (∼13%) and isometric (∼19%) quadriceps peak force, but with absolutely no effect of losartan on these outcomes. Furthermore, no changes were seen in satellite cell number with training, and most gene targets failed to show any changes induced by training or losartan treatment. We conclude that there does not appear to be any effect of AT1R blocking in elderly men during 4 mo of resistance training. Therefore, we do not find any support for using AT1R blockers for promoting muscle adaptation to training in humans. NEW & NOTEWORTHY Animal studies have suggested that blocking angiotensin II type I receptor (AT1R) enhances muscle regeneration and prevents disuse atrophy, but studies in humans are limited. Focusing on hypertrophy, satellite cells, and gene expression, we found that AT1R blocking did not result in any greater responses with 4 mo of resistance training. These results do not support previous findings and question the value of blocking AT1R in the context of preserving aging human muscle.

Nur77 Increases Glucose Transport in Mouse Skeletal Muscle Cells by Activating p38MAPK Under Lipotoxicity

2020 ◽  
Vol 10 (12) ◽  
pp. 1832-1836
Author(s):  
Yan Xu ◽  
Ming Zhang ◽  
Jianying Wang ◽  
Tianwei Gao
Keyword(s):  
Skeletal Muscle ◽  
Signaling Pathway ◽  
Glucose Transport ◽  
Cell Morphology ◽  
Glucose Concentration ◽  
Cell Activity ◽  
Muscle Cells ◽  
Control Group ◽  
P38mapk Signaling ◽  
And Control

Diabetes Mellitus (DM) is a common disease in clinic and belongs to a metabolic disease. Related studies have shown that Nur77 regulates sugar metabolism in a variety of tissue cells. Nur77 (orphan nuclear receptor) is a transcription factor and involves in glucose metabolism are different in skeletal muscle cells via p38MAPK signaling pathway. In the study, an IR model was to explore the mechanism of skeletal muscle IR. L6 myocytes were cultured and control, Nur77 knockout and Nur77 overexpression group was set followed by analysis of L6 muscle cell morphology, activity by MTT assay, glucose concentration by glucose oxidase-peroxidase (GOD-POD) p-p38MAPK and skeletal muscle glucose transporter-4 (GLUT4) level by western blot. After 8 to 12 hours of culture, the boundaries between cells were unknown with irregular order and no muscle-shaped structure. The cell morphology was mainly spindle-shaped and triangular. After 2 to 3 days, cell arrangement was regular and morphology was mainly spindle-shaped. The cell activity and glucose concentration in control group at different time points showed no differences which were significantly different in knockout and overexpression group with significantly higher cell activity and glucose concentration for overexpression group than knockout and control group (P < 0.05). In addition, overexpression group also showed significantly increased expression of p-p38MAPK4 and GLUT4. Nur77 can increase glucose transport under lipotoxic state by activating p38MAPK signaling pathway and increasing the protein expression of p-p38MAPK and GLUT4 in muscle cells.

scholarly journals Increased pyruvate dehydrogenase activity in skeletal muscle of growth-restricted ovine fetuses

2019 ◽  
Vol 317 (4) ◽  
pp. R513-R520 ◽  
Author(s):  
Alexander L. Pendleton ◽  
Laurel R. Humphreys ◽  
Melissa A. Davis ◽  
Leticia E. Camacho ◽  
Miranda J. Anderson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Pyruvate Dehydrogenase ◽  
Intrauterine Growth Restriction ◽  
Citrate Synthase ◽  
Pyruvate Dehydrogenase Kinase ◽  
Semitendinosus Muscle ◽  
Fetal Sheep ◽  
Pyruvate Dehydrogenase Phosphatase ◽  
And Control ◽  
Fetal Muscle

Fetal sheep with placental insufficiency-induced intrauterine growth restriction (IUGR) have lower fractional rates of glucose oxidation and greater gluconeogenesis, indicating lactate shuttling between skeletal muscle and liver. Suppression of pyruvate dehydrogenase ( PDH) activity was proposed because of greater pyruvate dehydrogenase kinase (PDK) 4 and PDK1 mRNA concentrations in IUGR muscle. Although PDK1 and PDK4 inhibit PDH activity to reduce pyruvate metabolism, PDH protein concentrations and activity have not been examined in skeletal muscle from IUGR fetuses. Therefore, we evaluated the protein concentrations and activity of PDH and the kinases and phosphatases that regulate PDH phosphorylation status in the semitendinosus muscle from placenta insufficiency-induced IUGR sheep fetuses and control fetuses. Immunoblots were performed for PDH, phosphorylated PDH (E1α), PDK1, PDK4, and pyruvate dehydrogenase phosphatase 1 and 2 (PDP1 and PDP2, respectively). Additionally, the PDH, lactate dehydrogenase (LDH), and citrate synthase (CS) enzymatic activities were measured. Phosphorylated PDH concentrations were 28% lower (P < 0.01) and PDH activity was 67% greater (P < 0.01) in IUGR fetal muscle compared with control. PDK1, PDK4, PDP1, PDP2, and PDH concentrations were not different between groups. CS and LDH activities were also unaffected. Contrary to the previous speculation, PDH activity was greater in skeletal muscle from IUGR fetuses, which parallels lower phosphorylated PDH. Therefore, greater expression of PDK1 and PDK4 mRNA did not translate to greater PDK1 or PDK4 protein concentrations or inhibition of PDH as proposed. Instead, these findings show greater PDH activity in IUGR fetal muscle, which indicates that alternative regulatory mechanisms are responsible for lower pyruvate catabolism.

Lower activity of oxidative key enzymes and smaller fiber areas in skeletal muscle of postobese women

1998 ◽  
Vol 275 (3) ◽  
pp. E487-E494 ◽  
Author(s):  
Anne Raben ◽  
Elsebeth Mygind ◽  
Arne Astrup
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Normal Weight ◽  
Fiber Types ◽  
Fiber Morphology ◽  
Key Enzymes ◽  
Control Subjects ◽  
Type Composition ◽  
And Control

Muscle fiber morphology and activities of four key enzymes, as well as energy metabolism, were determined in nine normal-weight postobese women and nine matched control subjects. No differences in fiber type composition, but a smaller mean fiber area and area of fiber types I and IIb, were found in postobese compared with control subjects ( P < 0.05). The activities of β-hydroxyacyl-CoA dehydrogenase (HADH) and citrate synthase (CS) were 20% lower in postobese than in control subjects ( P < 0.05). However, the activities of lactate dehydrogenase and lipoprotein lipase were not significantly different between postobese and control subjects. Basal metabolic rate and respiratory exchange ratio were also similar, but maximal oxygen uptake (V˙o 2 max) tended to be lower in postobese than in control subjects ( P = 0.06). When adjustments were made for differences inV˙o 2 max, HADH and CS were not different between postobese and control subjects. In conclusion, these data suggest that smaller fiber areas and lower enzyme activities, i.e., markers of aerobic capacity of skeletal muscle, but not fiber composition, may be factors predisposing to obesity.

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