scholarly journals Muskelwachstum und IGF-I bei Schweinen unterschiedlichen Geschlechts*

1999 ◽  
Vol 42 (6) ◽  
pp. 619-628
Author(s):  
S. Biereder ◽  
M. Wicke ◽  
G. von Lengerken ◽  
F. Schneider ◽  
W. Kanitz
Keyword(s):  
Skeletal Muscle ◽  
Blood Plasma ◽  
Muscle Fibre ◽  
Plasma Concentrations ◽  
Fibre Diameter ◽  
Postnatal Growth ◽  
Muscle Fibres ◽  
Triceps Brachii ◽  
Muscle Area ◽  
Igf I

Abstract. Title ofthe paper: Growth of skeletal muscle and IGF-I in pigs of different sex IGF-I is a pluripotent factor that is involved in regulation of growth, differentiation and a large number of functions in numerous tissues and their cells. IGF-I is synthesized by hepatocytes (endocrine role) and several extrahepatic tissues (e.g. skeletal muscle; autoerine and paracrine role). In our study, we describe the postnatal growth of the skeletal muscles in pigs of various sex taking into account the possible influence of endogenous IGF-I. The investigation was made on 42 crossbred pigs. Seven blood samples and 4 biopsy samples of two muscles (M. longissimus dorsi and M. triceps brachii) were taken for the determination of IGF-I blood plasma concentration and muscle fibre diameter, respectively as well as for further muscle structural and biochemical traits. IGF-I plasma concentrations show an increase during fattening with significantly highest levels for boars. Phenotypic differences between sows and boars in thickness of Shoulder muscle are proven after the day 181 with ultrasonography because significant differences were detected in mean muscle area of caput longum musculi triceps brachii between sows and boars and barrows (180th day of life). There are no significant differences in mean muscle fibre diameter of both muscles between sexes. A group of animals with high mean diameter in muscle fibres (day 200) of M. triceps brachii has significantly higher IGF-I concentrations in blood plasma than a group of animals with low muscle fibre diameter in the same muscle.

The effect of maternal nutrition level during mid-gestation on postnatal muscle fibre composition and meat quality in lambs

2016 ◽  
Vol 56 (5) ◽  
pp. 834 ◽  
Author(s):  
U. Sen ◽  
E. Sirin ◽  
U. Ensoy ◽  
Y. Aksoy ◽  
Z. Ulutas ◽  
...  
Keyword(s):  
Muscle Fibre ◽  
Meat Quality ◽  
Maternal Nutrition ◽  
Postnatal Growth ◽  
Quality Parameters ◽  
Carcass Composition ◽  
Daily Weight Gain ◽  
Control Group ◽  
Muscle Fibres ◽  
Muscle Area

Maternal nutrient intake during early- and mid-gestation can alter fetal growth and development with long-term consequences on the postnatal productivity and health of offspring. The aim of this study was to investigate the effects of maternal nutrition level during mid-gestation on postnatal growth rate, carcass composition, muscle fibre characteristics and meat quality in lambs. Ewes were fed from Days 30 to 80 of gestation as follows: 100% (control group, C), 50% (undernutrition, UN) or 175% (overnutrition, ON) of their daily requirement. During the rest of the gestation, the ewes in all groups were fed 100% of their daily requirements. Birth and weaning (at Day 90) weights of lambs born to ewes in nutritional groups were similar, but slaughter weights (at Day 150) and daily weight gain during finishing period of lambs born to the UN group were lower (P < 0.05). Similarly, a decrease in weights of semitendinosus (ST), semimembranosus and gastrocnemius muscles was observed in the lambs born to the UN group (P < 0.05). Lambs born to the ON group had a higher (P < 0.05) concentration of DNA in longissimus dorsi (LD) and ST muscles than UN groups, but they had a lower (P < 0.05) total protein and other proteins concentrations in LD and ST muscles than those to C and UN groups. Protein to DNA ratio in LD and ST muscles of lambs born to ON group were lower than those to C and UN groups (P < 0.05). However, lambs born to the ON group had a higher number of Type IIA and IIB muscle fibres in ST muscles but not in LD muscles than those in the C and UN groups (P < 0.05). Additionally an increase in the number of fibres/mm2 muscle area in lambs born to the ON group was observed in LD and ST muscles (P < 0.05). There were no significant differences between treatment groups in terms of meat quality parameters studied. This study confirms that maternal nutrition level during mid-gestation alters the postnatal growth and muscle fibre development of lambs.

scholarly journals Post-synaptic morphology of mouse neuromuscular junctions is linked to muscle fibre type

2020 ◽  
Author(s):  
Aleksandra M. Mech ◽  
Anna-Leigh Brown ◽  
Giampietro Schiavo ◽  
James N. Sleigh
Keyword(s):  
Motor Neuron ◽  
Muscle Fibre ◽  
Fibre Type ◽  
Neuromuscular Junctions ◽  
Fibre Diameter ◽  
Neuromuscular Diseases ◽  
Neuronal Morphology ◽  
Muscle Fibre Type ◽  
Muscle Membrane ◽  
Muscle Fibres

AbstractThe neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post-synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, ultimately facilitating the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, whether muscle fibre type impacts NMJ morphology and growth, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi-automated workflow called NMJ-morph to quantify features of pre- and post-synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild-type mice were dissected and compared at immature (post-natal day, P7) and early adult (P31-32) timepoints. Post-synaptic AChR morphology was found to be more variable between muscles than that of the motor neuron terminal and there were greater differences in the developing NMJ than at the mature synapse. Post-synaptic architecture, but not neuronal morphology or post-natal synapse growth, correlates with fibre type and is largely independent of muscle fibre diameter. Counter to previous observations, this study indicates that smaller NMJs tend to innervate muscles with higher proportions of fast twitch fibres and that NMJ growth rate is not conserved across all muscles. Furthermore, healthy pre- and post-synaptic NMJ morphological parameters were collected for five anatomically and functionally distinct mouse muscles, generating reference data that will be useful for the future assessment of neuromuscular disease models.Graphical Abstract

Time-dependent lateral transmission of force in skeletal muscle

2009 ◽  
Vol 465 (2108) ◽  
pp. 2441-2460 ◽  
Author(s):  
Yingxin Gao ◽  
Alan S. Wineman ◽  
Anthony M. Waas
Keyword(s):  
Skeletal Muscle ◽  
Relaxation Time ◽  
Muscle Fibre ◽  
Composite System ◽  
Stress Transfer ◽  
Time Dependent ◽  
Muscle Fibres ◽  
Strain History ◽  
Shear Stresses ◽  
Lateral Stress

There is experimental evidence to suggest that extensible connective tissues are mechanically time-dependent. In view of this, the mechanics of time-dependent lateral stress transfer in skeletal muscle is investigated by employing a viscoelastic shear lag model for the transfer of tensile stress between muscle fibres and the surrounding extracellular matrix (ECM) by means of shear stresses at the interface between the muscle fibre and the ECM. The model allows for both mechanical strains in the muscle as well as the strain owing to muscle contraction. Both the ECM and the muscle fibre are modelled as viscoelastic solids. As a result, time-dependent lateral stress transfer can be studied under a variety of loading and muscle stimulation conditions. The results show that the larger the muscle fibre creep time relative to the ECM relaxation time, the longer it takes for the muscle fibre stress to relax. It also shows that the response of the muscle–ECM composite system also depends on the characteristic time of a strain history relative to the characteristic relaxation time of the ECM. The results from the present model provide significant insight into the role of the parameters that characterize the response of the muscle composite system.

Blood Plasma Concentrations of Insulin-like Growth Factor-I (IGF-I) in Resting Standardbred Horses

2002 ◽  
Vol 163 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Z.J. Champion ◽  
B.H. Breier ◽  
W.E. Ewen ◽  
T.T. Tobin ◽  
P.J. Casey
Keyword(s):  
Growth Factor ◽  
Blood Plasma ◽  
Plasma Concentrations ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Intravenous infusion of insulin-like growth factor I in fetal sheep reduces hepatic IGF-I and IGF-II mRNAs

1996 ◽  
Vol 271 (6) ◽  
pp. R1632-R1637 ◽  
Author(s):  
K. L. Kind ◽  
J. A. Owens ◽  
F. Lok ◽  
J. S. Robinson ◽  
K. J. Quinn ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Growth Factor ◽  
Intravenous Infusion ◽  
Feedback Inhibition ◽  
Fetal Liver ◽  
Plasma Concentrations ◽  
Insulin Like Growth Factor ◽  
Fetal Sheep ◽  
Igf I

Liver contains the highest concentrations of insulin-like growth factor (IGF) I mRNA in adult rats and sheep and is a major source of circulating IGF-I. In rats, inhibition of hepatic IGF-I production by exogenous IGF-I has been reported. In fetal sheep, skeletal muscle and liver are major sites of IGF-I synthesis and potential sources of circulating IGF-I. To determine whether feedback inhibition of IGF gene expression in fetal liver or muscle by IGF-I occurs, IGF-I and IGF-II mRNAs were measured in these tissues after intravenous infusion of recombinant human IGF-I into fetal sheep. Infusion of IGF-I (26 +/- 4 micrograms.h-1.kg-1; n = 6) or saline (n = 6) commenced on day 120 of pregnancy (term = 150 days) and continued for 10 days. Plasma concentrations of IGF-I were threefold higher in infused fetuses at 130 days of gestation (P < 0.0003), whereas those of IGF-II were unchanged. IGF-I infusion reduced the relative abundance of IGF-I mRNA (P < 0.0002) and IGF-II mRNA (P < 0.01) in fetal liver by approximately 50% but did not alter IGF-I or IGF-II mRNA in skeletal muscle. These results indicate that IGF-I inhibits the expression of both IGF-I and IGF-II genes in fetal liver and that IGF gene expression in fetal liver and muscle is differentially regulated by IGF-I.

Ontogenic study of Expression of IGF-I and Gh-Receptor (GHR) mRNA in pig Liver and Skeletal Muscle.

1993 ◽  
Vol 1993 ◽  
pp. 151-151
Author(s):  
J.M. Brameld ◽  
P.A. Weller ◽  
R.S. Gilmour ◽  
P.J. Buttery
Keyword(s):  
Skeletal Muscle ◽  
Cell Types ◽  
Muscle Fibres ◽  
Alternative Promoters ◽  
Pig Liver ◽  
Gh Receptor ◽  
Age Related ◽  
Igf I ◽  
Class 1 ◽  
Stimulation Of

Many of the effects of growth hormone are now thought to be mediated via the stimulation of insulin-like growth factor-I (IGF-I) production by many tissues, especially the liver, with this stimulation being dependent upon the presence of the GH-receptor (GHR). IGF-I gene expression occurs via alternative promoters giving rise to class 1 and 2 transcripts, of which class 2 is thought to be preferentially responsive to GH (Saunders, Dickson, Pell & Gilmour, 1991).The effects of IGF-I include the stimulation of DNA synthesis (mitogenesis) and protein synthesis in most cell types, together with the differentiation of many cell types into mature tissue, including the differentiation of muscle cells into muscle fibres. Thus the GH/IGF-I axis has been found to play a major part in the control of animal growth. For this reason, we studied the age related changes in IGF-I and GHR mRNA expression in pig liver and skeletal muscle.

Relation between body size and muscle fibre diameter in the newborn lamb

1956 ◽  
Vol 47 (4) ◽  
pp. 449-455 ◽  
Author(s):  
D. M. Joubert
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Muscle Fibre ◽  
Fibre Diameter ◽  
Rectus Femoris ◽  
Muscle Fibres ◽  
Muscle Fibre Size ◽  
Fibre Size ◽  
Ewe Lambs ◽  
Positive Correlations

1. An investigation is reported in which the relationship was examined between body size and muscle fibre size of nineteen newborn lambs and including twelve males and seven females. Body size was measured in terms of the dead body weight and that of the dressed carcass, while muscle fibre size was estimated on the basis of the mean crossdiameter of 150 fibres per lamb.2. It was shown that the dressing (or carcass) percentage tends to increase with an increase in body weight, from 42·26% at a body weight of 2000 g. to 49·04% at 7000 g.3. Of the 2850 cross-diameters recorded, the majority (33·8%) of the fibres measured between 8·0 and 9·6 μ, while individual fibres varied in size from 1·6 to 22·4 μ.4. Highly significant, positive correlations were shown to exist between both body (r = 0·996) and carcass (r = 0·946) weight, and mean muscle fibre diameter, indicating that differences in size between the lambs may be accounted for largely by corresponding variations in the size of individual muscle fibres.5. Of the three muscles sampled m. gastrocnemius had the largest mean fibre diameter (10·38μ), followed in decreasing order by m. rectus femoris (9·72 μ) and m. longissimus dorsi (9·09 μ). These inter-muscle differences were significant at the 1% level of probability.6. Ram lambs had significantly thicker muscle fibres (10·32 μ) than ewe lambs (8·72 μ), but also weighed the heavier and produced heavier dressed carcasses. Some evidence was produced, however, in support of the theory that at comparable weights males possess thinner individual, and therefore a greater number of fibres than females.

Evidence for an essential role for calcium in excitation-contraction coupling in skeletal muscle

1964 ◽  
Vol 160 (981) ◽  
pp. 504-512 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibre ◽  
Calcium Ions ◽  
Essential Role ◽  
Mechanical Response ◽  
Frog Heart ◽  
Muscle Fibres ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Spontaneous Action

The events and processes that link the electrical events which occur at the surface of a muscle fibre with the contractile process that takes place within the fibre, have been a continuing source of interest. Recently attention has been concentrated on the role played by calcium ions in linking these two events. As often happens in physiological investigations, the idea that calcium ions play an essential role in excitation-contraction coupling is not new. As long ago as 1883 Ringer demonstrated that the frog heart fails to contract and remains relaxed when calcium ions are absent from its perfusion fluid. Later it was shown that under this condition the rhythmic spontaneous action potentials of this preparation are still present in an only slightly modified form (Mines 1913). It was known at that time that the depolarization of the muscle fibre membrane is the electrical event responsible for initiating the mechanical response (Biedermann 1896) and although this point has been disputed from time to time, the evidence presently available makes it obvious that this is the case. One explanation of these observations is that the action potential or depolarization permits or promotes the movement of calcium ions from the surface to the interior of the muscle fibre and that these ions then initiate the mechanical response. A working hypothesis of this type was proposed by Sandow (1952). However, until fairly recently the only direct evidence supporting such an hypothesis was the demonstration by Heilbrunn & Wiercinski (1947) that calcium was the only physiologically occurring cation which would cause shortening when injected into bits of skeletal muscle fibres in low concentrations. This effect was later confirmed under more physiological conditions by Niedergerke (1955). Although there is considerable evidence of recent origin showing that calcium ions play an essential role in coupling in smooth and cardiac muscles, for the sake of brevity attention will be concentrated on skeletal muscle in the present discussion.

scholarly journals Impairments in contractility and cytoskeletal organisation cause nuclear defects in nemaline myopathy

2019 ◽  
Author(s):  
Jacob A Ross ◽  
Yotam Levy ◽  
Michela Ripolone ◽  
Justin S Kolb ◽  
Mark Turmaine ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Nuclear Envelope ◽  
Muscle Fibre ◽  
Nemaline Myopathy ◽  
Cytoskeletal Proteins ◽  
Muscle Fibres ◽  
Filament Structure ◽  
Transcriptional Alterations ◽  
Fibre Growth ◽  
Chromatin Arrangement

AbstractNemaline myopathy (NM) is a genetically heterogeneous skeletal muscle disorder caused by mutations predominately affecting contractile filaments, in particular thin filament structure and/or regulation. The underlying cellular pathophysiology of this disease remains largely unclear. Here, we report novel pathological defects in skeletal muscle fibres of mice and patients with NM, including disrupted nuclear envelope, altered chromatin arrangement, and disorganisation of the cortical cytoskeleton. We demonstrate that such nuclear defects are caused by impairment of muscle fibre contractility, and that cytoskeletal organisation determines nuclear morphology. Our results overlap with findings in diseases caused by mutations in nuclear envelope or cytoskeletal proteins. Given the important role of nuclear shape and envelope in regulating gene expression, and the cytoskeleton in maintaining muscle fibre integrity, our findings are likely to underlie some of the hallmarks of NM, which include broad transcriptional alterations, arrested muscle fibre growth, contractile filament disarray and altered mechanical properties.

Muscle growth and development in normal-sex-ratio and all-female diploid and triploid Atlantic salmon

1999 ◽  
Vol 202 (15) ◽  
pp. 1991-2016 ◽  
Author(s):  
I.A. Johnston ◽  
G. Strugnell ◽  
M.L. McCracken ◽  
R. Johnstone
Keyword(s):  
Sex Ratio ◽  
Atlantic Salmon ◽  
Muscle Fibre ◽  
Satellite Cells ◽  
Muscle Growth ◽  
Fibre Diameter ◽  
Muscle Fibres ◽  
Female Fish ◽  
Right Hand ◽  
Triploid Fish

Muscle development and growth were investigated in diploid populations of normal-sex-ratio and all-female Atlantic salmon (Salmo salar L.) and their triploid counterparts produced by high-pressure treatment. Somites were formed at the rate of 6 h-1 in both diploids and triploids at 6 degrees C. The rostral-to-caudal development of myotubes, myofibrils and acetylcholinesterase staining at the myosepta was slightly more advanced in triploid than in diploid fish, although the differences were smaller than among individual families. The c-met receptor tyrosine kinase was used as a molecular marker for the satellite cells involved in postembryonic muscle growth. Satellite cell nuclei comprised 17.5 % of total myonuclei in smolts and they were 24 % more abundant in diploid than in triploid fish. Cells expressing the myogenic regulatory factor myf-6, a marker of satellite cells committed to differentiation, represented 14.8 % of total myonuclei in diploids and 12.5 % in triploids. At ambient temperatures, the number of white muscle fibres in normal-sex-ratio fish increased more than 30-fold between the alevin and smolt stages, and approximately 3.5-fold further during the first year of seawater growth. The rate of muscle fibre recruitment in seawater stages was significantly greater in diploid than in triploid fish, reaching 1162 fibres day-1 and 608 fibres day-1, respectively, in all-female groups 800 days post-hatching. For 42 cm fork-length fish, there were approximately one-third more muscle fibres per myotome in diploid than in triploid groups, 649 878 and 413 619, respectively, for all-female fish. The probability density function of muscle fibre diameters in each fish was estimated using non-parametric smoothing techniques, and the mean densities for diploids (fD) and triploids (fT) were calculated. The peak fibre diameter was approximately 20 (micro)m in all age classes, irrespective of ploidy. Distinct bimodal distributions of muscle fibre diameter were evident in all groups 775 days and 839 days post-hatching, reflecting seasonal cycles of fibre recruitment. fD and fT were compared using a non-parametric bootstrap technique and the reference band representing the null-hypothesis indicated that there was no difference with ploidy. Reference bands for normal-sex-ratio fish at 315 days and 470 days indicated that diploids had a higher percentage of smaller-diameter fibres and that triploid distributions had a thicker right-hand tail. Similar differences in fD and fT of muscle fibre diameters were found for all-female fish, although the statistical evidence was less strong. Reference bands indicated differences in the middle range of the distributions of muscle fibre diameter in fish 620–775 days post-hatch, with triploids having a thicker right-hand tail. Thus, a lower density of satellite cells was associated with reduced rates of fibre recruitment but a compensatory increase in muscle fibre hypertrophy in triploid compared with diploid fish.

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