title: Involvement of insulin-like growth factor-1 in the effect of caloric restriction: regulation of plasma adiponectin and leptin.
abstract: Insulin-like growth factor (IGF)-1 signaling might partly mediate effects of caloric restriction (CR), an experimental intervention for increasing longevity in mammals. The present study evaluated effects of recombinant human (rh)IGF-1 infusion on adipokine levels in CR and transgenic (Tg) dwarf rats with the reduced growth hormone-IGF-1 axis, which shared similar body weight and food intake. At 9 months of age, each rat received a continuous infusion of rhIGF-1 for 14 days, and rats received an injection of glucose after overnight fasting. Infusion of rhIGF-1 had metabolic effects in all rat groups although it did not affect insulin sensitivity in any of the groups. In addition, plasma adiponectin was decreased to the control group levels and plasma leptin was further reduced in CR and Tg rats. The similarity of phenotypes and adipokine responses to rhIGF-1 between CR and Tg rats supports a role for reduced IGF-1 signaling in the CR effect.
authors.affiliation: Pathology & Gerontology, Nagasaki University Graduate School of Biomedical Sciences, 12-4 Sakamoto 1-chome, Nagasaki City 852-8523, Japan. hyamaza@net.nagasaki-u.ac.jp
authors.forename: Haruyoshi
authors.initials: H
authors.lastname: Yamaza
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Komatsu
authors.forename: Kazuo
authors.initials: K
authors.lastname: To
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Toyama
authors.forename: Takuya
authors.initials: T
authors.lastname: Chiba
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Higami
authors.forename: Isao
authors.initials: I
authors.lastname: Shimokawa
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000375:Aging / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D031204:Caloric Restriction; D005500:Follow-Up Studies; D018507:Gene Expression Regulation, Developmental; D013006:Growth Hormone / Q000097:blood* / Q000235:genetics; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage* / Q000493:pharmacokinetics; D020738:Leptin / Q000097:blood*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone