Nandrolone decanoate treatment induces changes in contractile responses of rat untrained fast‐twitch skeletal muscle

Joumaa, Wissam H.; Serrurier, B.; Bigard, Xavier; Léoty, Claude

doi:10.1046/j.1365-201x.2002.00988.x

Cited by 10 publications

(21 citation statements)

References 25 publications

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“…Our data are in agreement with recent studies demonstrating that drug treatment produces changes in 146 K-contracture of isolated sedentary rat edl and soleus cells associated with a shift to more negative potential of voltage-dependent activation without a change in the time constant of contracture relaxation [27].…”

Section: Discussionsupporting

confidence: 83%

“…This proposal is in line with recent reports showing that the administration of nandrolone decanoate to sedentary animals results in alterations in the excitation-contraction coupling mechanism at the cellular level [16,27] and produces different changes in the contractile responses developed by fast and slow muscles.…”

Section: Discussionsupporting

confidence: 80%

“…The results of Joumaa et al [27] confirm this observation and show that, after 6 weeks of nandrolone decanoate treatment, Ca 2ϩ sensitivity was increased in both soleus and edl muscles without a change in MHC isoform expression.…”

Section: Discussionsupporting

confidence: 79%

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Nandrolone Decanoate Reduces Changes Induced by Hindlimb Suspension in Voltage-Dependent Tension of Rat Soleus Muscle

Bouhlel¹,

Joumaa²,

Léoty³

2003

Jpn.J.Physiol

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In skeletal muscles, the depolarization of action potentials in transverse tubules induces a movement of charged voltage sensors [1] within the dihydropyridine receptors [2]. The voltage sensors then activate the opening of Ca 2ϩ -release channels in the sarcoplasmic reticulum to generate tension. In order to look at the excitation-contraction coupling mechanism directly without complications of additional effects due to the action potential mechanism, potassium contractures were generally used rather than twitch-tension responses.Isometric tension generated by prolonged depolarization (K ϩ contracture) allows analysis of the relationship between myoplasmic calcium concentration or tension and T-tubule membrane potential, which has been shown to be different in slow-and fasttwitch fibers [3]. Thus, activation and inactivation processes involved in depolarization-contraction coupling can be examined in skeletal muscles using the K ϩ contracture technique [3][4][5].

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Section: Discussionsupporting

confidence: 83%

Section: Discussionsupporting

confidence: 80%

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Nandrolone Decanoate Reduces Changes Induced by Hindlimb Suspension in Voltage-Dependent Tension of Rat Soleus Muscle

Bouhlel¹,

Joumaa²,

Léoty³

2003

Jpn.J.Physiol

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“…It is assumed that the K ϩ contracture amplitude depends on activation of the voltage sensor in the transverse tubule membrane, and that relaxation depends on inactivation of the process regulating calcium release from the sarcoplasmic reticulum and the ability of the sarcoplasmic reticulum to pump calcium [28]. We have recently found [27] that, in edl, nandrolone decanoate treatment induces an increase in K ϩ contracture tension that could be accounted for by a shift in the voltage-dependent activation and inactivation curve to more negative membrane potential Persistent Effects of Anabolic Steroids values, which became similar to soleus. Thus, it was proposed that, in contrast to soleus where a delayed potentiating of K ϩ contracture was found, in edl, the effect on K ϩ contracture tension due to hormone treatment was reversible after ending treatment.…”

Section: Caffeine Contracturesmentioning

confidence: 99%

“…Thus, it seems reasonable to suggest that nandrolone decanoate could alter one or more of these events such that force production is increased. We have recently shown that a short period of nandrolone decanoate treatment in untrained rat produces more pronounced changes in the contractile responses of edl than of soleus muscles by acting on the voltage dependency of activation and inactivation of contraction and on the sensitivity of contractile proteins without change in the MHC isoforms to Ca 2ϩ [27]. Therefore, we proposed that the absence of a significant difference between twitch tension of treated (5 wk of drug treatment followed by 5 wk of arrest) and control animals was associated with a reversible effect on the voltage dependency of activation and inactivation of contraction and on the sensitivity of contractile proteins to Ca 2ϩ .…”

Section: Caffeine Contracturesmentioning

confidence: 99%

Post-Effects of Nandrolone Decanoate Treatment on Contractile Responses of Rat Skeletal Muscles

Joumaa

Bouhlel²,

Léoty³

2002

Jpn.J.Physiol

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steroids have been a subject of great interest in recent years. However, animal studies have given contradictory results, ranging from an insignificant effect [1] to improvement in physical working capacity [2], strength [3][4][5], protein synthesis [6], lysosomal and mitochondrial activities [7], and functioning of the sarcotubular system [8]. In general, many factors make it difficult to compare results, such as the species used, the gender and age of animals, the type of muscle studied [3,[9][10][11], experimental conditions, the specific anabolic androgenic steroids used [12], the doses, the mode and period of administration [6,[13][14][15], and the diet [5].In skeletal muscle, contraction is generated when action potentials invade the interior of individual fibers along the membrane of the transverse tubule system (T-tubule). The passage of the action potential is followed by an increase in free myoplasmic calcium concentration that activates troponin and allows crossbridge cycling and contraction. Changes in Ca 2ϩ concentration depend on an interaction between different processes: T-tubule action potential, voltage-sensor response, putative excitation-contraction coupling mechanism, the properties of the Ca 2ϩ release channel, Ca 2ϩ diffusion to and through myofibrils, Ca Japanese Journal of Physiology, 52, 479-487, 2002 Key words: anabolic androgenic steroid, contraction. Abstract:The post-effects of nandrolone decanoate treatment (15 mg · kg Ϫ1 · week Ϫ1) were studied on contractile responses of isolated small bundles of intact slow-(soleus) and fast-(extensor digitorum longus, edl) twitch fibers in rat. Five weeks of treatment induced, in edl, an increase in the amplitude of twitch (55%) and K ϩ contracture (32%) without significant change in the time constant of relaxation and caffeine contracture. In soleus, an increase in the amplitude of twitch (35%) and caffeine contracture (0.2 mM: 218%, 0.5 mM: 88%, 5 mM: 28%, and 10 mM: 25%) was observed without change in K ϩ contracture characteristics. In addition to these effects, 10 weeks of drug treatment increased the amplitude of soleus K ϩ contracture (29%) and edl caffeine contracture (0.2 mM: 247%, 0.5 mM: 170%, 5 mM: 29%, and 10 mM: 45%), and reduced the 50% recovery time for K ϩ contracture (EC 50 ) (soleus: 37%, edl: 12%). After 5-week treatment followed by 5-week arrest, as compared to the control group, no change in the amplitude of twitch, K ϩ or caffeine contractures was found in edl. In soleus, although no significant difference was observed in the amplitude of twitch, the amplitude of K ϩ (35%) and caffeine contractures (0.2 mM: 227%, 0.5 mM: 128%) remained greater than the control group. Moreover, the EC 50 values were prolonged (46%) in soleus, whereas no significant difference was observed in edl. The present work suggests that nandrolone decanoate treatment induced differential post-effects on contractile responses developed in slowand fast-twitch skeletal muscles by acting differently on the different steps of the excitation-contractio...

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Myosin heavy chain expression pattern as a marker for anabolic potency: desoxymethyltestosterone (madol), norandrostendione and testosterone repress MHC-IIb expression and stimulate MHC-IId/x expression in orchiectomized rat gastrocnemius muscle

et al. 2010

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Both 19-norandrostenedione (estr-4-ene-3,17-dione, NOR) and desoxymethyltestosterone (17alpha-methyl-5alpha-androst-2-en-17beta-ol, DMT or "madol") are 'designer steroids' misused for doping purposes in the bodybuilding scene. We have previously characterized the pharmacological profile of madol and identified potential adverse side effects. The aim of this study was to investigate the anabolic potency of NOR, madol and the reference substance testosterone propionate (TP). Besides wet weight of the M.levator ani (LA), we examined the effects on muscle fiber type composition and myosin heavy chain (MHC) expression in the M.gastrocnemius (Gas) muscle as additional markers for anabolic potency. A Hershberger assay was performed, where orchiectomized (orchi) male Wistar rats were treated subcutaneously with NOR, madol, TP or vehicle control (all 1 mg/kg BW/day) for 12 days. Wet weights of the Gas, LA, prostate and seminal vesicle were examined to determine anabolic and androgenic effects. Fiber type composition of the Gas muscle was analyzed using ATPase staining, and MHC protein profiles were determined by silver stain and Western blot analysis. NOR and madol exhibited strong anabolic and weak androgenic potency by stimulating growth of the LA but not the prostate and seminal vesicle. Skeletal muscle fiber type composition characterized by ATPase staining was not significantly altered between the treatment groups, although there was a tendency toward lower levels of type IIB and increased type IIA fibers in all treatment groups relative to orchi. MHC protein expression determined by Western blot and silver stain analysis revealed that MHC IId/x was significantly up-regulated, while MHC IIb was significantly down-regulated in NOR, madol and TP groups relative to orchi. There were no significant differences for MHC IIa and MHC I expression between groups. Results suggest that the observed MHC expression shift could serve as a molecular marker to determine anabolic activity of anabolic steroids at least in skeletal muscle of orchi rats. The molecular mechanisms as well as the androgen-dependent regulation of MHC expression in intact skeletal muscle remain to be further investigated.

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Nandrolone decanoate treatment induces changes in contractile responses of rat untrained fast‐twitch skeletal muscle

Cited by 10 publications

References 25 publications

Nandrolone Decanoate Reduces Changes Induced by Hindlimb Suspension in Voltage-Dependent Tension of Rat Soleus Muscle

Nandrolone Decanoate Reduces Changes Induced by Hindlimb Suspension in Voltage-Dependent Tension of Rat Soleus Muscle

Post-Effects of Nandrolone Decanoate Treatment on Contractile Responses of Rat Skeletal Muscles

Myosin heavy chain expression pattern as a marker for anabolic potency: desoxymethyltestosterone (madol), norandrostendione and testosterone repress MHC-IIb expression and stimulate MHC-IId/x expression in orchiectomized rat gastrocnemius muscle

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