Myosin heavy chain expression pattern as a marker

Authors: S Frese M Velders B Schleipen W Schänzer W Bloch P Diel

Publish Date: 2010/10/19

Volume: 85, Issue: 6, Pages: 635-643

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Abstract

Both 19norandrostenedione estr4ene317dione NOR and desoxymethyltestosterone 17alphamethyl5alphaandrost2en17betaol 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 Mlevator ani LA we examined the effects on muscle fiber type composition and myosin heavy chain MHC expression in the Mgastrocnemius 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 upregulated while MHC IIb was significantly downregulated 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 androgendependent regulation of MHC expression in intact skeletal muscle remain to be further investigated

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