Cytochrome c mRNA and alpha-actin mRNA in muscles of rats fed beta-GPA.
A diet of 1% beta-guanidinopropionic acid (beta-GPA) fed to rats for weeks results in decreased muscle adenosine triphosphate and creatine phosphate concentrations (J. Biol. Chem. 249: 1060-1063, 1974), increased activities of selected mitochondrial enzymes (Biochem. J. 232: 125-131, 1985), and atrophied type IIb fibers (Lab. Invest. 33: 151-158, 1975). The hypothesis of the present study was that chronic beta-GPA feeding would increase cytochrome c mRNA in muscle and would decrease alpha-skeletal actin mRNA in type IIb muscle. Data collected supported, in part, the hypothesis. After 22 days of a 1% beta-GPA diet, cytochrome c mRNA was increased 60-67% in muscles with inherently low cytochrome c mRNA but was not altered in muscles with higher cytochrome c mRNA levels. alpha-Skeletal actin mRNA was unchanged in muscles with low and high cytochrome c mRNA after 22 days of 1% beta-GPA. After 66 days of beta-GPA feeding, both cytochrome c mRNA and alpha-skeletal actin mRNA were decreased 18 and 26%, respectively, per unit of total RNA, in white quadriceps muscle. At the same time muscles composed of predominantly type II fibers atrophied 22%, whereas type I muscle size was unaltered. These data suggest that high-energy phosphate levels could play some role in adaptive changes in muscle composition.
Lai
M M
MM
Department of Physiology and Cell Biology, University of Texas Medical School, Houston 77225.
Booth
F W
FW
D000199:Actins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003574:Cytochrome c Group / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D006146:Guanidines / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000201:enzymology / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D010725:Phosphocreatine / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D000199:Actins; D003574:Cytochrome c Group; D006146:Guanidines; D011422:Propionates; D012333:RNA, Messenger; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; C005775:guanidinopropionic acid