scholarly journals Activity of mu- and m-calpain in regenerating fast and slow twitch skeletal muscles.

1996 ◽  
Vol 43 (4) ◽  
pp. 693-700 ◽  
Author(s):  
J Moraczewski ◽  
E Piekarska ◽  
M Zimowska ◽  
M Sobolewska
Keyword(s):  
Intracellular Calcium ◽  
Soleus Muscle ◽  
Muscle Regeneration ◽  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Slow Twitch ◽  
Edl Muscle ◽  
Calpain Ii ◽  
Complete Regeneration

Calpains--non-lysosomal intracellular calcium-activated neutral proteinases, form a family consisting of several distinct members. Two of the isoenzymes: mu (calpain I) and m (calpain II) responded differently to the injury during complete regeneration of Extensor digitorum longus (EDL) muscle and partial regeneration of Soleus muscle. In the crushed EDL the level of m-calpain on the 3rd and 7th day of regeneration was higher than in non-operated muscles, whereas the activity of this calpain in injured Soleus decreased. The level of mu-calpain in EDL oscillated irregularly during regeneration whereas in Soleus of both injured and contralateral muscles its level rapidly rose. Our results support the hypothesis that m-calpain is involved in the process of fusion of myogenic cells whereas mu-calpain plays a significant but indirect role in muscle regeneration.

Aberrant expression of myosin isoforms in skeletal muscles from mice lacking the rev-erbAα orphan receptor gene

2005 ◽  
Vol 288 (2) ◽  
pp. R482-R490 ◽  
Author(s):  
P. Pircher ◽  
P. Chomez ◽  
F. Yu ◽  
B. Vennström ◽  
L. Larsson
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Thyroid Hormone Receptor ◽  
Extensor Digitorum ◽  
Type I ◽  
Wild Type ◽  
Slow Twitch ◽  
Isoform Expression

The rev-erbAα orphan protein belongs to the steroid nuclear receptor superfamily. No ligand has been identified for this protein, and little is known of its function in development or physiology. In this study, we focus on 1) the distribution of the rev-erbAα protein in adult fast- and slow-twitch skeletal muscles and muscle fibers and 2) how the rev-erbAα protein influences myosin heavy chain (MyHC) isoform expression in mice heterozygous (+/−) and homozygous (−/−) for a rev-erbAα protein null allele. In the fast-twitch extensor digitorum longus muscle, rev-erbAα protein expression was linked to muscle fiber type; however, MyHC isoform expression did not differ between wild-type, +/−, or −/− mice. In the slow-twitch soleus muscle, the link between rev-erbAα protein and MyHC isoform expression was more complex than in the extensor digitorum longus. Here, a significantly higher relative amount of the β/slow (type I) MyHC isoform was observed in both rev-erbAα −/− and +/− mice vs. that shown in wild-type controls. A role for the ratio of thyroid hormone receptor proteins α1 to α2 in modulating MyHC isoform expression can be ruled out because no differences were seen in MyHC isoform expression between thyroid hormone receptor α2-deficient mice (heterozygous and homozygous) and wild-type mice. Therefore, our data are compatible with the rev-erbAα protein playing an important role in the regulation of skeletal muscle MyHC isoform expression.

scholarly journals Effects of dexamethasone treatment on insulin-stimulated rates of glycolysis and glycogen synthesis in isolated incubated skeletal muscles of the rat

1987 ◽  
Vol 246 (2) ◽  
pp. 551-554 ◽  
Author(s):  
B Leighton ◽  
R A J Challiss ◽  
F J Lozeman ◽  
E A Newsholme
Keyword(s):  
Soleus Muscle ◽  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Glycogen Synthesis ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Hexose Transport ◽  
Dexamethasone Treatment ◽  
Longus Muscle ◽  
Lactate Formation

1. Rats were treated with dexamethasone for 4 days before measurement of the rates of lactate formation [which is an index of hexose transport; see Challiss, Lozeman, Leighton & Newsholme (1986) Biochem. J. 233, 377-381] and glycogen synthesis in response to various concentrations of insulin in isolated incubated soleus and extensor digitorum longus muscle preparations. 2. The concentration of insulin required to stimulate these processes half-maximally in soleus and extensor digitorum longus muscles isolated from control rats was about 100 muunits/ml. 3. Dexamethasone increases the concentration of insulin required to stimulate glycolysis half-maximally in soleus and extensor digitorum longus preparations to 250 and 300 muunits/ml respectively. The respective insulin concentrations necessary to stimulate glycogen synthesis half-maximally were about 430 and 370 muunits/ml for soleus and extensor digitorum longus muscle preparations isolated from steroid-treated rats. 5. Dexamethasone treatment did not change the amount of insulin bound to soleus muscle.

Glycogenesis and glyconeogenesis in skeletal muscle: effects of pH and hormones

1990 ◽  
Vol 258 (4) ◽  
pp. E693-E700 ◽  
Author(s):  
A. Bonen ◽  
J. C. McDermott ◽  
M. H. Tan
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Extensor Digitorum ◽  
Effects Of Ph ◽  
Slow Twitch ◽  
Highly Correlated ◽  
Fast Twitch

We examined the effects of selected hormones and pH on the rates of glyconeogenesis (L-[U-14C]-lactate----glycogen) and glycogenesis (D-[U-14C]glucose----glycogen) in mouse fast-twitch (FT) and slow-twitch muscles incubated in vitro (37 degrees C). Glyconeogenesis and glycogenesis increased linearly with increasing concentrations of lactate (5-20 mM) and glucose (2.5-10 mM), respectively, in both muscles. Glyconeogenesis was approximately three- to fourfold greater in the extensor digitorum longus (EDL) than in the soleus, whereas basal glycogenesis was twofold greater in the soleus muscle than in the EDL. Lactate accounted for up to 5% of the glycogen formed in the soleus and up to 32% in the EDL relative to the rates of glycogenesis (i.e., 5 mM glucose + 10 nM insulin) in each muscle. Corticosterone (10(-12)-10(-6) M) failed to alter glyconeogenesis, whereas this hormone reduced glycogenesis. Insulin (10 nM) markedly stimulated glycogenesis but failed to stimulate glyconeogenesis. The rates of both glycogenesis and glyconeogenesis were pH sensitive, with optimal rates at pH 6.5-7.0 in both muscles. Glyconeogenesis increased by 49% in the soleus and by 39% EDL at pH 6.5 compared with pH 7.4. Glycogenesis increased in the soleus (SOL) and EDL in the absence (SOL: +22%; EDL: +52%) and presence of insulin (SOL: +22%; EDL: +51%) at pH 6.5 when compared with pH 7.4. In additional experiments with the perfused rat hindquarter, rates of glyconeogenesis were shown to be highly correlated with proportion of FT muscle fibers in a muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of corticosterone on protein degradation in isolated rat soleus and extensor digitorum longus muscles

1996 ◽  
Vol 148 (3) ◽  
pp. 501-507 ◽  
Author(s):  
S B Bowes ◽  
N C Jackson ◽  
D Papachristodoulou ◽  
A M Umpleby ◽  
P H Sönksen
Keyword(s):  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Acute Effect ◽  
Term Treatment ◽  
Extensor Digitorum ◽  
Protein Breakdown ◽  
Significant Difference ◽  
Corticosterone Treatment ◽  
Edl Muscle ◽  
And Control

Abstract The net catabolic effect of glucocorticoids on protein metabolism is well documented but the acute and chronic effect of glucocorticoids on protein breakdown remains controversial. In the present studies protein breakdown was measured by the release of tyrosine from the isolated soleus and extensor digitorum longus (EDL) muscles of control rats and rats treated with corticosterone (10 mg/100 g body weight/day) for 5 days. The effect of corticosterone in arresting growth was confirmed since corticosterone-treated rats weighed significantly less than control rats after 2, 3, 4 and 5 days of treatment (P<0·001). Furthermore, the weights of soleus and EDL muscles from corticosterone-treated rats were significantly reduced (P<0·001, at least P<0·05 respectively) compared with muscles from control rats on days 3–5. In the EDL muscle tyrosine release was significantly elevated after corticosterone treatment for 2 days (257 ± 21 nmol/g tissue/h, P<0·05), 3 days (205 ± 9 nmol/g tissue/h, P<0·01), 4 days (255 ± 20 nmol/g tissue/h, P<0·005) and 5 days (218 ± 8 nmol/g tissue/h, P<0·05) compared with EDL from control rats (192 ± 13, 171 ± 7, 187 ± 7, 180 ± 12 nmol/g tissue/h respectively). In the soleus muscle, tyrosine release was significantly elevated after corticosterone treatment for 2 days (226 ± 14 nmol/g tissue/h, P<0·001), 3 days (223 ± 16 nmol/g tissue/h, P<0·001) and 4 days (199 ± 10 nmol/g tissue/h, P<0·001) compared with control rats (158 ± 7, 132 ± 6 and 153 ± 7 nmol/g tissue/h respectively). After 5 days there was no significant difference in tyrosine release from soleus muscle between corticosterone-treated (176 ± 15 nmol/g tissue/h) and control rats (157 ± 6 nmol/g tissue/h). Plasma glucose concentrations were not significantly different in rats treated with corticosterone and control rats whilst insulin levels were significantly raised in the corticosterone-treated rats on all days compared with control rats (P<0·05 on day 1; P<0·001 on days 2, 3, 4 and 5). It is suggested that insulin may have prevented hyperglycaemia developing in the corticosterone-treated rats. Results from these studies indicate that the acute effect of glucocorticoids is to increase muscle proteolysis but this is not maintained with longer-term treatment. Journal of Endocrinology (1996) 148, 501–507

Elevated endothelial-cell-stimulating angiogenic factor activity in rodent glycolytic skeletal muscles

1991 ◽  
Vol 81 (2) ◽  
pp. 267-270 ◽  
Author(s):  
R. G. Cooper ◽  
C. M. Taylor ◽  
J. J. Choo ◽  
J. B. Weiss
Keyword(s):  
Endothelial Cell ◽  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Capillary Density ◽  
Extensor Digitorum ◽  
Angiogenic Factor ◽  
Type I ◽  
Type Ii ◽  
Factor Activity ◽  
Angiogenic Activity

1. Capillary density is greater in skeletal muscles comprised of predominantly oxidative (type I) fibres than in those comprised of mainly glycolytic (type II) fibres. In order to investigate further the angiogenic mechanisms involved in muscle capillarization, endothelial-cellstimulating angiogenic factor activities in various rodent skeletal muscles were compared. 2. Eleven untrained adult male Wistar rats were killed and the predominantly oxidative (type I) muscles, soleus and heart, the predominantly glycolytic (type II) muscle, extensor digitorum longus, and the mixed-fibre muscle, gastrocnemius, were removed. Each sample was separately homogenized and centrifuged and the supernatants were diafiltered to isolate the low-molecular-mass fraction containing endothelial-cell-stimulating angiogenic activity. This was assayed for its ability to activate latent collagenase and was expressed as units, where 1 unit represents the percentage activation of the enzyme h−1 (mg of protein in the supernatant)−1. 3. The results (medians and ranges) demonstrated significantly greater endothelial-cell-stimulating angiogenic factor activity in extensor digitorum longus muscle (2.14 units, 0.62–2.87 units, n = 13) than in soleus (0.82 units, 0.59–1.79 units, n = 15), gastrocnemius (0.34 units, 0.28–0.40 units, n = 4) or heart (0.43 units, 0.16–0.52 units, n = 11) (P< 0.01 for each) muscle. 4. These findings suggest that endothelial-cell-stimulating angiogenic activity in muscle is either inversely or not related to the local capillary density, which may be at or near a maximum in physiologically contracting, predominantly oxidative muscles.

Histochemical fiber type distribution and epinephrine sensitivity in normal and cross-transplanted rat muscles

1987 ◽  
Vol 65 (6) ◽  
pp. 1205-1212 ◽  
Author(s):  
John M. Kennedy ◽  
Franz S. F. Mong ◽  
James L. Poland
Keyword(s):  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Fiber Type ◽  
Extensor Digitorum ◽  
Glycogen Depletion ◽  
Type Distribution ◽  
Control Muscle ◽  
Glycogen Concentration ◽  
Fiber Type Distribution ◽  
Epinephrine Dose

The metabolic integrity of fully regenerated transplants was investigated by measuring induced changes in glycogen concentration. The extensor digitorum longus and the soleus muscles were cross transplanted: the extensor digitorum longus into the soleus muscle bed (SOLT) and the soleus muscle into the extensor digitorum longus bed (EDLT). The histochemical fiber type distribution of the regenerated muscles was determined and was found to transform in cross-transplanted EDLT and SOLT. After transplantation and regeneration, both muscles had initially low glycogen concentrations. However, the EDLT glycogen concentration was not significantly different from that of the contralateral extensor digitoium longus control muscle after 60 days. In the SOLT, glycogen gradually increased but remained less than in the contralateral soleus control muscle. SOLT and control soleus muscles responded with a significant glycogen depletion to an epinephrine dose two orders of magnitude less than the lowest dose affecting glycogen levels in EDLT and extensor digitorum longus muscles. These results indicate that transplanted muscles are capable of regenerating normal glycogenolytic responses and that the sensitivity of the response observed depends on the site of transplantation and is related to the type of innervation and histochemical fiber type.

Insulin binding and 2-deoxy-D-glucose uptake in fast- and slow-twitch mouse skeletal muscle at 18 and 37 °C

1984 ◽  
Vol 62 (12) ◽  
pp. 1460-1465 ◽  
Author(s):  
Wendy M. Watson-Wright ◽  
Meng H. Tan ◽  
Arend Bonen
Keyword(s):  
Extensor Digitorum Longus ◽  
Insulin Binding ◽  
Extensor Digitorum ◽  
Insulin Degradation ◽  
Response Curves ◽  
Slow Twitch Muscle ◽  
Two Temperatures ◽  
Higher Temperature ◽  
Slow Twitch ◽  
Insulin Responsiveness

Insulin binding, insulin degradation, and 2-deoxyglucose uptake were examined at 18 and 37 °C in soleus and extensor digitorum longus muscles of mice. Insulin binding and degradation were greater in the soleus than in the extensor digitorum longus at both temperatures (p < 0.05). At 37 °C, binding was decreased in both muscles while percentage degradation was increased in comparison with 18 °C (p < 0.05). Dose–response curves (percentage of binding at 4 nM of insulin) remained the same for both muscles at the two temperatures. Basal (no insulin) 2-deoxyglucose uptake was increased at 37 °C in the extensor digitorum longus but not the soleus. Insulin responsiveness in terms of the amount of 2-deoxyglucose taken up per femtomole of insulin bound was almost identical for the two muscles at 18 °C, whereas at 37 °C it was increased more in the soleus than in the extensor digitorum longus. The results indicate that in the presence of physiological concentrations of insulin (0.2–4 nM), insulin binding trends are minimally affected by increased temperature. In contrast, the ability of insulin to stimulate 2-deoxyglucose uptake varies between the two temperatures, and at the higher temperature between fast- and slow-twitch muscle.

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