Altered IGF-I and IGFBPs in senescent male and female rats.
The effects of senescence on muscle characteristics and the insulin-like growth factor I (IGF-I) pathway were assessed in male and female BN/F344 rats. The mass and total ATPase activity of gastrocnemius and plantaris muscles were reduced with age and to a greater extent in males than in females. The mass and total ATPase activity of soleus muscle were not significantly altered with age. Circulating IGF-I was also significantly reduced with age, 60% in females and 21% in males. Circulating IGF-binding protein 3 (IGFBP-3) was reduced with age. In liver and gastrocnemius muscle, mRNAs for IGF-1, IGFBP-2, and IGFBP-3 were analyzed in young and aged males of two strains, BN/F344 and Sprague-Dawley. In BN/F344 rats, liver mRNAs were unchanged with age. Also in BN/F344 rats, muscle mRNAs for IGFBP-2, and IGFBP-3 displayed nonsignificant trends toward increase with age. In aged Sprague-Dawley males, liver mRNA for IGF-I was increased 15% and muscle mRNA for IGFBP-2 was increased 110%. Thus, different age-related changes in the growth hormone (GH)/IGF pathway occur in males and females between the sexes and strains. These changes may play a role in the muscle atrophy associated with senescence.
Severgnini
S
S
Department of Internal Medicine and Clinical Therapy, University of Pavia, Italy.
Lowenthal
D T
DT
Millard
W J
WJ
Simmen
F A
FA
Pollock
B H
BH
Borst
S E
SE
D000251:Adenosine Triphosphatases / Q000032:analysis; D000375:Aging / Q000097:blood* / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006133:Growth Substances / Q000097:blood; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000235:genetics; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000235:genetics; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood* / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D016014:Linear Models; D008099:Liver / Q000378:metabolism; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000201:enzymology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000201:enzymology / Q000378:metabolism; D009133:Muscular Atrophy / Q000209:etiology; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344; D011919:Rats, Inbred Strains; D017207:Rats, Sprague-Dawley; D012737:Sex Factors
D006133:Growth Substances; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D000251:Adenosine Triphosphatases