Insulin-like growth factor-1 and myostatin mRNA expression in muscle: comparison between 62-77 and 21-31 yr old men.
The present study was done to determine the effect of age on muscle concentrations of mRNAs encoding two growth factors that are thought to be important regulators of muscle mass: insulin-like growth factor-1 (IGF-1) and myostatin. Quantitative RT-PCR assays indicated that the mean IGF-1 mRNA concentration in older muscle (62-77 yr, n=15 men) was approximately 25% less, per ng total RNA (P<0.005), than in young adult muscle (21-31 yr, n=12 men). One third of the older men had IGF-1 mRNA levels below the lowest concentration observed in young muscle. Myostatin mRNA concentrations were similar in young and old muscle. Muscle mass and myofibrillar protein synthesis rates among eight older men did not correlate with either IGF-1 or myostatin mRNA levels. We conclude that IGF-1 gene expression in muscle tends to decline with normal aging. The functional significance is uncertain.
Welle
Stephen
S
University of Rochester Medical Center, Endocrinology, P.O. Box 693, 601 Elmwood Avenue, Rochester, NY 14642, USA. stephen_welle@urmc.rochester.edu
Bhatt
Kirti
K
Shah
Bharati
B
Thornton
Charles
C
D000328:Adult; D000368:Aged; D000375:Aging / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D055435:Myostatin; D012333:RNA, Messenger / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000235:genetics*
C525911:MSTN protein, human; D055435:Myostatin; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D007334:Insulin-Like Growth Factor I