Protein synthesis studies in skeletal muscle of aging rats. I. Alterations in nitrogen composition and protein synthesis using a crude polyribosome and pH 5 enzyme system.
The effect of aging on rat skeletal muscle protein synthesis was studied using a cell-free system. The activity of crude polyribosomes from hind-limb skeletal muscle was reduced by 40% in aged animals (22 to 24 months) and by 20% in the mature (12 months) animal compared with young (2 month) rats. In a poly Uridylic-acid-directed incorporation system the ribosomes from aged and mature animals showed a decrease in activity. Sucrose density gradient analysis also demonstrated a loss of heavy polyribosomes in aged and mature animals. The pH 5 enzyme fraction from aged and mature animals was less efficient than that from young rats in support of protein synthesis, suggesting a decreased activity of soluble factors. In conclusion, aging leads to a progressive decline in the efficiency of protein synthesis, associated with both the ribosome and soluble fractions of the cell.
D000367:Age Factors; D000375:Aging; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002474:Cell-Free System; D002499:Centrifugation, Density Gradient; D008297:Male; D009132:Muscles / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis*; D011132:Polyribosomes / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D000596:Amino Acids; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012343:RNA, Transfer; D009584:Nitrogen