Nandrolone decanoate modulates cell cycle regulation in functionally overloaded rat soleus muscle.
Functionally overloading rat soleus muscle by synergist ablation induces a rapid increase in mass. Muscle remodeling during the first week of overload is critical for the overload-induced growth. Anabolic steroid modulation of this overload-induced remodeling response is not well understood. The purpose of this study was to determine whether pretreatment with nandrolone decanoate, a clinically administered anabolic steroid, alters muscle morphology and gene expression related to muscle growth during the initiation of functional overload in the rat soleus muscle. Adult (5 mo) male Fisher 344 x Brown Norway rats were randomly assigned to control (Sham), 3-day functional overload (OV), nandrolone decanoate administration (ND), or 3-day functional overload with nandrolone decanoate administration (OV+ND) treatment groups. Morphologically, OV increased the percentage of small (361%) and large (150%) fibers and expanded the ECM 50%. ND administration decreased the 3-day OV induction of small fibers 51% and nuclei associated with the ECM 20%. ND administration also attenuated the induction of cell cycle regulator p21 (64%) and myogenin (37%) mRNAs after 3 days of overload. These data demonstrate that nandrolone decanoate pretreatment can alter morphological and cell cycle regulator expression related to muscle growth at the onset of functional overload.
McClung
Joseph M
JM
Integrative Muscle Biology Laboratory, Division of Applied Physiology, Exercise Science Department, University of South Carolina, Columbia, SC 29208, USA.
Mehl
Kristen A
KA
Thompson
Raymond W
RW
Lowe
Larry L
LL
Carson
James A
JA
D045930:Anabolic Agents / Q000494:pharmacology*; D000818:Animals; D015152:Blotting, Northern; D002453:Cell Cycle / Q000187:drug effects*; D049109:Cell Proliferation; D019938:Cyclin D1 / Q000378:metabolism; D005786:Gene Expression Regulation; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000502:physiology / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000166:cytology* / Q000502:physiology*; D018006:Myogenic Regulatory Factors / Q000378:metabolism; D009277:Nandrolone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000077603:Nandrolone Decanoate; D015689:Oncogene Protein p21(ras) / Q000378:metabolism; D009929:Organ Size; D010766:Phosphorylation; D005082:Physical Exertion / Q000502:physiology*; D012313:RNA / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D020133:Reverse Transcriptase Polymerase Chain Reaction; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism
D045930:Anabolic Agents; D018006:Myogenic Regulatory Factors; D019938:Cyclin D1; D012313:RNA; D007334:Insulin-Like Growth Factor I; D009277:Nandrolone; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D015689:Oncogene Protein p21(ras); D000077603:Nandrolone Decanoate