Effects of aging and caloric restriction on IGF-I, IGF-I receptor, IGFBP-3 and IGFBP-4 gene expression in the rat stomach and colon

Lance M. Hallberg, Yuji Ikeno, Ella Englander, George H. Greeley

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

The purpose of this study was to determine the effects of aging and caloric restriction (CR) on insulin-like growth factor-I (IGF-I), IGF-I receptor (IGF-IR), IGF-binding protein-3 (IGFBP-3) and IGFBP-4 expression in the stomach and colon of male Fischer 344 rats. Stomach and colonic RNA were prepared from ad libitum (AL) fed or long-term CR rats. Stomach IGF-I, IGFBP-3 and IGFBP-4 mRNA levels increased significantly (P≤0.05), while colonic IGF-I mRNA levels were unchanged in aged AL rats. In aged CR rats, stomach IGFBP-3 mRNA levels decreased. Stomach and colonic IGF-IR mRNA levels declined with aging in AL and CR rats (P≤0.05). Colonic IGFBP-3 mRNA levels decreased significantly with aging in AL rats. There were no changes in colonic IGFBP-4 mRNA levels in aged AL or CR rats. Increased expression of stomach IGF-I, IGFBP-3 and IGFBP-4 in aged AL rats suggests that the stomach attempts to preserve IGF activity by increasing local expression of IGF-I and IGFBPs. Because the aging colon has a propensity to develop cancer, it may adapt to increased colonic IGF-I expression by reducing IGF-IR and IGFBP-3 expression. Additionally, CR lowers colonic IGF-I expression in aged rats (24 months) which may also be a protective adaptive mechanism. Copyright (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)37-44
Number of pages8
JournalRegulatory Peptides
Volume89
Issue number1-3
DOIs
StatePublished - May 10 2000

Keywords

  • Gastrointestinal
  • Insulin-like Growth Factor
  • Insulin-like Growth Factor Binding Proteins

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Clinical Biochemistry
  • Cellular and Molecular Neuroscience

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