Distribution and levels of insulin-like growth factor I mRNA across the life span in the Brown Norway X Fischer 344 rat brain

• Published in: Brain research Vol. 804; no. 1; pp. 79 - 86
• Main Authors: NIBLOCK, M. M, BRUNSO-BECHTOLD, J. K, LYNCH, C. D, INGRAM, R. L, MCSHANE, T, SONNTAG, W. E
• Format: Journal Article
• Language: English
• Published: London Elsevier 31.08.1998; Amsterdam; New York, NY
• Subjects: Aging - metabolism; Animals; Biological and medical sciences; Brain - metabolism; Development. Senescence. Regeneration. Transplantation; Fundamental and applied biological sciences. Psychology; Hybridization, Genetic; In Situ Hybridization; Insulin-Like Growth Factor I - genetics; Rats; Rats, Inbred BN; Rats, Inbred F344; RNA, Messenger - metabolism; Tissue Distribution; Vertebrates: nervous system and sense organs; Vertebrata; Senescence; Mammalia; Messenger RNA; Rat; Rodentia; Central nervous system; Distribution; Insulin like growth factor 1; Age; Brain (vertebrata)
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(98)00645-3

Previous studies have reported changes in insulin-like growth factor I (IGF-I) mRNA expression during early postnatal development of the rat brain. Although changes in IGF-I gene expression have been documented in a wide range of central nervous system structures during early development and investigated in the hippocampus during aging, no study has compared changes in IGF-I gene expression in different brain regions across the life span. The present study assessed the distribution of IGF-I gene expression using in situ hybridization in rats aged 2-30 months. Dot blots were used as a quantitative assessment of cortical IGF-I mRNA. Results indicate that both the distribution and levels of brain IGF-I mRNA do not change significantly between 2 and 30 months of age in the rat. However, in spite of relatively constant levels of mRNA, other studies from our laboratory have demonstrated that cortical IGF-I protein levels decrease 36.6% between 11 and 32 months of age, suggesting that IGF-I function is decreased with increasing age.