Localization and regulation of IGF-I and IGF-II mRNA
Insulin-like growth factors I and II (IGF-I and -H) are peptide mitogens that exert a wide range of biological actions in many tissues and cell types. The actions of the IGFs include metabolic and differentiative effects as well as their capacity to stimulate cell proliferation. (Humbel 1984; Froesch et al. 1985; Van Wyk 1984). Traditionally the IGFs were considered as hormones that are transported in the circulation to act on target cells in an endocrine fashion (Humbel 1984; Froesch et al. 1985; Van Wyk et al. 1984). Based on studies of perfused liver (Schwander et al. 1983), liver derived cell lines (Moses et al. 1980), and primary cultures oliver cells (Richmond et al. 1985), the liver was considered the major source of serum IGFs. The IGFs do not appear to be stored in the liver to an appreciable extent, however, since the concentrations of IGFs are higher in blood perfusing the liver than in extracts of liver. More recently, cultured expiants of many tissues in addition to liver have been found to secrete immunoreactive IGFs into media (D’Ercole et al. 1984). Extracts of multiple tissues in addition to liver also contain higher concentrations of immunoreactive IGF than can be attributed to concentrations in blood perfusing the tissues (D’Ercole et al. 1984, 1986). These observations have raised the possibility that in addition to the endocrine actions of IGFs transported to target cells via the circulation, there may be paracrine or autocrine actions of IGFs synthesized locally in multiple tissues (D’Ercole et al. 1984,1986).
KeywordsChoroid Plexus eDNA Probe Synthetic Oligomer Oligomer Probe Liver Derive Cell Line
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- Humbel RE (1984) Insulin-like growth factors, somatomedins, and multiplication stimulating activity chemistry. In: Li CH (ed) Hormonal Proteins and Peptides: Growth Factors, vol 12. Academic, New York, pp 57–79Google Scholar
- Ott L (1977) In: Ott L (ed) An Introduction to Statistical Methods and Data Analysis. Duxbury, Belmont, pp 354–407Google Scholar
- Roberts CT Jr, Lasky SR, Lowe WL, Seaman WT, LeRoith D (1987) Molecular cloning of rat insulin-like growth factor I complementary deoxyribounucleic acids: differential messenger ribonucleic acid processing and regulation by growth hormone in extra-hepatic tissues. Mol Cell Endocrinol 1: 243–248CrossRefGoogle Scholar
- Schalch DS, Heinrich UE, Draznin B, Johnson CJ, Miller LL (1979) Role of the liver in regulating somatomedin activity: hormonal effects on the synthesis and release of insulin-like growth factor and its carrier protein by the isolated perfused rat liver. Endocrinology 104:1143–1151PubMedCrossRefGoogle Scholar
- Van Wyk JJ (1984) The somatomedins: biological actions and physiologic control mechanisms. In: Li CH (ed) Hormonal Proteins and Peptides: Growth Factors, vol 12. Academic, New York, pp 81–125Google Scholar