Actin and creatine kinase mRNAs in rat levator ani and vastus muscles as a function of androgen status

1990 ◽  
Vol 68 (4) ◽  
pp. 1548-1561 ◽  
Author(s):  
G. Boissonneault ◽  
P. Chapdelaine ◽  
R. R. Tremblay
Keyword(s):  
Creatine Kinase ◽  
Vastus Lateralis ◽  
Control Level ◽  
Levator Ani ◽  
In Vitro Translation ◽  
Levator Ani Muscle ◽  
Time Intervals ◽  
Actin Expression ◽  
Fast Twitch

The plasticity of two selected mRNAs was studied in two typical fast-twitch muscles at different time intervals after orchiectomy (GDX). The levator ani muscle of the rat (LA) is exquisitely sensitive to androgens, whereas the superficial vastus lateralis (SVL) lacks such sensitivity. In vitro translation of RNA isolated from both tissues indicated that actin was among the most repressed proteins of the LA at day 10 postsurgery (GDX-10 days), whereas the template activity of the SVL mRNAs remains virtually unmodified. We used an available actin cDNA and demonstrated that the expression of the LA actin message is reduced by 85% in GDX-10 days and can be recovered after testosterone propionate (TP) injections (GDX + TP). In contrast, the actin expression in SVL remains constant up to day 20 postsurgery. In the LA, the expression of creatine kinase (CK) mRNA was increased 140% in GDX-5 days and decreased 34 and 17% in GDX-10 days and GDX-20 days, respectively, although the measured CK activity, as well as the in vitro translation of the message, remained elevated in those two latter groups. Control level of the CK mRNA expression was recovered in the GDX + TP group. Again, the expression of the message was unchanged in SVL, suggesting that the protein synthesis of this skeletal muscle is far less sensitive to androgen deprivation than that of the LA muscle.

scholarly journals Steroidal Androgens and Nonsteroidal, Tissue-Selective Androgen Receptor Modulator, S-22, Regulate Androgen Receptor Function through Distinct Genomic and Nongenomic Signaling Pathways

2008 ◽  
Vol 22 (11) ◽  
pp. 2448-2465 ◽  
Author(s):  
Ramesh Narayanan ◽  
Christopher C. Coss ◽  
Muralimohan Yepuru ◽  
Jeffrey D. Kearbey ◽  
Duane D. Miller ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Levator Ani ◽  
Reproductive Organs ◽  
Cross Reactivity ◽  
Levator Ani Muscle ◽  
Xenopus Laevis Oocyte ◽  
Muscle Weight

Abstract Androgen receptor (AR) ligands are important for the development and function of several tissues and organs. However, the poor oral bioavailability, pharmacokinetic properties, and receptor cross-reactivity of testosterone, coupled with side effects, place limits on its clinical use. Selective AR modulators (SARMs) elicit anabolic effects in muscle and bone, sparing reproductive organs like the prostate. However, molecular mechanisms underlying the tissue selectivity remain ambiguous. We performed a variety of in vitro studies to compare and define the molecular mechanisms of an aryl propionamide SARM, S-22, as compared with dihydrotestosterone (DHT). Studies indicated that S-22 increased levator ani muscle weight but decreased the size of prostate in rats. Analysis of the upstream intracellular signaling events indicated that S-22 and DHT mediated their actions through distinct pathways. Modulation of these pathways altered the recruitment of AR and its cofactors to the PSA enhancer in a ligand-dependent fashion. In addition, S-22 induced Xenopus laevis oocyte maturation and rapid phosphorylation of several kinases, through pathways distinct from steroids. These studies reveal novel differences in the molecular mechanisms by which S-22, a nonsteroidal SARM, and DHT mediate their pharmacological effects.

Recovery in skeletal muscle contractile function after prolonged hindlimb immobilization

1985 ◽  
Vol 59 (3) ◽  
pp. 916-923 ◽  
Author(s):  
R. H. Fitts ◽  
C. J. Brimmer
Keyword(s):  
Contractile Function ◽  
Vastus Lateralis ◽  
Weight Ratio ◽  
Contractile Properties ◽  
Shortening Velocity ◽  
Slow Twitch ◽  
Isometric Twitch ◽  
Fast Twitch ◽  
Muscle Contractile

Contractile properties of slow-twitch soleus (SOL), fast-twitch extensor digitorum longus (EDL), and fast-twitch superficial region of the vastus lateralis were determined in vitro (22 degrees C) in rats remobilized after prolonged (3 mo) hindlimb immobilization (IM). For all muscles the muscle-to-body weight ratio was significantly depressed by IM, and the ratios failed to completely recover even after 90 days. The contractile properties of the fast-twitch muscles were less affected by IM than the slow-twitch SOL. The IM shortened the SOL isometric twitch duration due to a reduced contraction and half-relaxation time. These parameters returned to control levels by the 14th day of recovery. Peak tetanic tension (Po, g/cm2) declined with IM by 46% in the SOL but showed no significant change in the fast-twitch muscles. After IM the SOL Po (g/cm2) recovered to control values by 28 days. The recovery of Po in absolute units (g) was considerably slower and did not return to control levels until 60 (SOL) to 90 (EDL) days. The maximum shortening velocity was not altered by IM in any of the muscles studied. These results demonstrate that both fast- and slow-twitch skeletal muscles possess the ability to completely recover normal contractile function following prolonged periods of hindlimb IM.

scholarly journals Paxilline Prevents the Onset of Myotonic Stiffness in Pharmacologically Induced Myotonia: A Preclinical Investigation

2020 ◽  
Vol 11 ◽  
Author(s):  
Kerstin Hoppe ◽  
Tina Sartorius ◽  
Sunisa Chaiklieng ◽  
Georg Wietzorrek ◽  
Peter Ruth ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Bk Channel ◽  
Muscle Membrane ◽  
Vastus Lateralis Muscle ◽  
Wild Type ◽  
Myotonia Congenita ◽  
Twitch Force ◽  
Fast Twitch ◽  
Muscle Specimen

Reduced Cl− conductance causes inhibited muscle relaxation after forceful voluntary contraction due to muscle membrane hyperexcitability. This represents the pathomechanism of myotonia congenita. Due to the prevailing data suggesting that an increased potassium level is a main contributor, we studied the effect of a modulator of a big conductance Ca2+- and voltage-activated K+ channels (BK) modulator on contraction and relaxation of slow- and high-twitch muscle specimen before and after the pharmacological induction of myotonia. Human and murine muscle specimens (wild-type and BK−/−) were exposed to anthracene-9-carboxylic acid (9-AC) to inhibit CLC-1 chloride channels and to induce myotonia in-vitro. Functional effects of BK-channel activation and blockade were investigated by exposing slow-twitch (soleus) and fast-twitch (extensor digitorum longus) murine muscle specimens or human musculus vastus lateralis to an activator (NS1608) and a blocker (Paxilline), respectively. Muscle-twitch force and relaxation times (T90/10) were monitored. Compared to wild type, fast-twitch muscle specimen of BK−/− mice resulted in a significantly decreased T90/10 in presence of 9-AC. Paxilline significantly shortened T90/10 of murine slow- and fast-twitch muscles as well as human vastus lateralis muscle. Moreover, twitch force was significantly reduced after application of Paxilline in myotonic muscle. NS1608 had opposite effects to Paxilline and aggravated the onset of myotonic activity by prolongation of T90/10. The currently used standard therapy for myotonia is, in some individuals, not very effective. This in vitro study demonstrated that a BK channel blocker lowers myotonic stiffness and thus highlights its potential therapeutic option in myotonia congenital (MC).

COMPARISON BETWEEN THE BINDING OF 19-NORTESTOSTERONE, 5α-DIHYDROTESTOSTERONE AND TESTOSTERONE IN RAT PROSTATE AND BULBOCAVERNOSUS/LEVATOR ANI MUSCLE

1976 ◽  
Vol 70 (3) ◽  
pp. 379-387 ◽  
Author(s):  
M. KRIEG ◽  
M. DENNIS ◽  
K. D. VOIGT
Keyword(s):  
Specific Binding ◽  
Levator Ani ◽  
Levator Ani Muscle ◽  
Binding Affinities ◽  
Receptor Sites ◽  
Rat Prostate ◽  
Layer Chromatography ◽  
In Vitro Data

SUMMARY Specific binding of [3H]19-nortestosterone in the 100000 g cytosol of the rat bulbocavernosus/levator ani muscle (BCLA) and prostate was demonstrated by agargel electrophoresis at low temperature and compared qualitatively and quantitatively with the binding of tritiated testosterone and 5α-dihydrotestosterone (5α-DHT). Both tissues showed a greater binding affinity for 5α-DHT than for 19-nortestosterone, with testosterone binding the least well of the three. The relative binding affinities in the BCLA and prostate were: 19-nortestosterone: testosterone = 1·4, 19-nortestosterone: 5α-DHT = 0·7. The differences were statistically significant (P < 0·02). The concentrations of receptor sites for 5α-DHT were 171 ± 20 (s.d.) fmol/mg prostatic cytosol protein and 24 ± 4 (s.d.) fmol/mg BCLA cytosol protein. The in-vitro metabolism of the three steroids in both tissues was also investigated by thin-layer chromatography. After incubating for 2 h at 0 °C the prostate was shown to reduce 26% of the 5α-DHT to androstanediols whilst the BCLA showed a 5% conversion. Testosterone was converted by the prostate to 5α-DHT (10%) and the androstanediols (6%) whilst the BCLA showed little activity in this respect. Comparing these in-vitro data with in-vivo findings from the literature, in both organs there is a positive correlation of the extent of binding in vitro to the stimulation of growth in vivo, bearing in mind that testosterone is metabolized to 5α-DHT in the prostate whilst in the BCLA, 5α-reductase is essentially absent.

EFFECTS OF INSULIN ON THE INTACT LEVATOR ANI MUSCLE OF THE RAT

1967 ◽  
Vol 56 (2) ◽  
pp. 295-307 ◽  
Author(s):  
A. Arvill ◽  
K. Ahrén
Keyword(s):  
Amino Acids ◽  
Actinomycin D ◽  
Muscle Protein ◽  
Levator Ani ◽  
Levator Ani Muscle ◽  
Intracellular Accumulation ◽  
Insulin Stimulation ◽  
Significant Stimulation ◽  
Stimulation Of

ABSTRACT The effects of insulin on the rate of intracellular accumulation and incorporation into the protein of some normal amino acids (glycine-3H, leucine-14C and valine-14C) in the intact levator ani muscle of the rat were studied in vitro. The effect of puromycin on the accumulation of these amino acids as well as on the accumulation of the model amino acid α-aminoisobutyric acid-14C (AIB-14C) was examined. In addition the effect of insulin on the incorporation of adenine-14C into the muscle RNA as well as on the effect of actinomycin D added to the incubation medium were also investigated. The insulin stimulated AIB-14C transport is described by the formulation of Michaelis-Menten and approximate values of Km and Vmax are calculated for this transport in the levator ani muscle. Insulin was found to stimulate the intracellular accumulation of glycine-3H and AIB-14C, while a significant decrease was found in the accumulation of leucine-14C and valine-14C. Insulin also stimulated the incorporation of glycine-3H and leucine-14C into the muscle protein. When puromycin was added to the medium, no radioactivity was found in the protein fraction and insulin then stimulated the intracellular accumulation of glycine-3H, leucine-14C and AIB-14C. A slight but significant stimulation with insulin was found on the incorporation of adenine-14C into the RNA-fraction of the levator ani muscle. The addition of actinomycin D was found to inhibit this effect of insulin, but did not change the insulin stimulation of the AIB-14C accumulation. The results are discussed in relation to our present knowledge of the different in vitro effects of insulin.

Effect of disuse on sarcoplasmic reticulum in fast and slow skeletal muscle

1982 ◽  
Vol 243 (3) ◽  
pp. C156-C160 ◽  
Author(s):  
D. H. Kim ◽  
F. A. Witzmann ◽  
R. H. Fitts
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Time Course ◽  
Vastus Lateralis ◽  
Control Level ◽  
Type I ◽  
Uptake Capacity ◽  
Three Samples ◽  
Fast Twitch

The effect of 6 wk of hindlimb immobilization on rat skeletal muscle sarcoplasmic reticulum (SR) was determined in the slow-twitch, type I soleus (SOL), the fast-twitch, type IIA deep region of the vastus lateralis (DVL), and the fast-twitch, type IIB superficial region of the vastus lateralis (SVL). Immobilization produced a significant decline in the Ca2+ uptake rate (Vmax) of SR vesicles from the slow SOL (0.930 +/- 0.116 to 0.365 +/- 0.071 mumol Ca2+ . mg-1 . min-1), while the SR Vmax increased in the fast SVL (2.763 +/- 0.133 to 5.209 +/- 0.687) and was unaltered in the DVL. Vesicles from the fast SVL and DVL also exhibited a higher total Ca2+ uptake capacity following immobilization. An evaluation of the time course of the immobilization-mediated effect revealed an increased Ca2+ uptake capacity in all three samples after 1 wk. In the SOL total Ca2+ uptake returned to control level after 2 wk, while in the fast-twitch muscles the higher capacities were maintained. The Ca2+-stimulated SR ATPase activity was not altered in any of the muscles studies, although the total SR ATPase activity increased twofold in the slow SOL.

scholarly journals Stimulation of creatine kinase activity in rat skeletal tissue in vivo and in vitro by protease-resistant variants of parathyroid hormone fragments

1995 ◽  
Vol 309 (1) ◽  
pp. 85-90 ◽  
Author(s):  
D Sömjen ◽  
V Vargas ◽  
A Waisman ◽  
E Wingender ◽  
W Tegge ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Parathyroid Hormone ◽  
Double Mutant ◽  
Bone Cells ◽  
Specific Activity ◽  
Control Level ◽  
Maximal Stimulation ◽  
Stimulation Of

We have reported that mid-region fragments of human parathyroid hormone (hPTH), exemplified by hPTH-(28-48), stimulated [3H]thymidine incorporation into DNA and increased the specific activity of the brain-type isoenzyme of creatine kinase (CK) in both skeletal-derived cell cultures (ROS 17/2.8 cells) and immature rat epiphyseal cartilage and diaphyseal bone, without stimulating cyclic AMP synthesis which is a prerequisite for bone resorption. In the present study, substitution of amino acids in hPTH-(28-48), which resulted in increased resistance to proteolysis, produced variants that stimulated skeletal systems at two orders of magnitude lower concentration than the wild-type fragment. We modified hPTH-(28-48) at Leu-37 by replacement with Met, Thr or Val. Under conditions in which 20% of the native hPTH-(28-48) resisted proteolysis by cathepsin D for 6 h, approx. 40% of the L37V mutant and 70% of the L37T mutant remained intact. Substitution of Met for Phe-34 in addition to Thr for Leu-37, or the substitution of Met for Phe-34 alone, produced 100%-resistant fragments. These variants at residue 34 caused maximal stimulation of CK in ROS 17/2.8 cells at 0.24 nM compared with 24 nM for hPTH-(28-48). The double mutant stimulated CK activity significantly in immature rats, at a minimum dose of 12.5 ng/rat, and caused maximal stimulation at 125 ng/rat, a 10-fold lower dose than for hPTH-(28-48). The effect of the double mutant lasted up to 24 h which differs from the stimulation by hPTH-(28-48) in which CK specific activity returns to the control level at 24 h. This same dose also significantly stimulated CK activity in gonadectomized rats. These results show the advantage of using protease-resistant mid-region variants of hPTH-(28-48) to stimulate bone cells, in terms of lower doses and longer duration of effectiveness, both in vitro and in vivo.

DIFFERENTIAL EFFECTS OF CASTRATION AND DENERVATION ON PROTEIN SYNTHESIS IN THE LEVATOR ANI MUSCLE OF THE RAT

1972 ◽  
Vol 54 (1) ◽  
pp. 3-NP ◽  
Author(s):  
M. BUREŠOVÁ ◽  
E. GUTMANN ◽  
V. HANZLÍKOVÁ
Keyword(s):  
Protein Synthesis ◽  
Levator Ani ◽  
Mature Male ◽  
Male Rats ◽  
Levator Ani Muscle ◽  
Female Rat ◽  
Weight Changes ◽  
Immature Male ◽  
Testosterone Administration

SUMMARY The effects of testosterone on weight changes, incorporation of labelled precursors into RNA and proteins, and on ultrastructure of the levator ani muscle of male rats in which castration or denervation was performed, were studied. No increase of weight occurred in the denervated levator ani muscle after castration. There was no increase in the incorporation of labelled precursors into RNA and proteins in vitro in mature rats, if the muscle was denervated. However, incorporation still increased when denervation was performed in sexually immature animals. The levator ani muscle, which normally undergoes postnatal involution in the female rat, could be maintained even after postnatal denervation if testosterone was administered at birth, the hormone acting as a nerve-independent trophic agent. The increase of protein synthesis in the levator ani of mature, male, castrated animals, induced by testosterone administration, was abolished after denervation of the muscle. The activating influence of testosterone upon protein synthesis was, however, still present in immature male animals.

THE LEVATOR ANI MUSCLE OF THE RAT AS AN INTACT PREPARATION SUITABLE FOR IN VITRO INVESTIGATIONS

1966 ◽  
Vol 52 (2) ◽  
pp. 325-336 ◽  
Author(s):  
A. Arvill ◽  
K. Ahrén
Keyword(s):  
Levator Ani ◽  
Male Rats ◽  
Levator Ani Muscle ◽  
List Type ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Incubation Periods ◽  
Total Tissue

ABSTRACT A method is described of dissecting out and incubating the levator ani muscle of immature male rats, keeping its normal connections to the rest of the perineal complex. In order to find out whether this isolated preparation remained intact with undamaged cell membranes, comparisons were made between this preparation of the levator ani muscle and a cut preparation of the same muscle, and also between the levator ani muscle and the intact and cut preparations of the diaphragm. The following determinations were made: Distribution of sucrose-14C in vivo and in vitro Distribution of inulin-14C in vitro Distribution of D-xylose-14C in vitro Total tissue water content Potassium concentration in the medium after different incubation periods. It is concluded that it is possible to dissect out the levator ani muscle with undamaged cells and that this preparation can be both suitable and useful for in vitro investigations.

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