Molecular cloning of rat insulin-like growth factor I complementary deoxyribonucleic acids: differential messenger ribonucleic acid processing and regulation by growth hormone in extrahepatic tissues |
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| Authors: | C T Roberts S R Lasky W L Lowe W T Seaman D LeRoith |
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| Institution: | Diabetes Branch, National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, Maryland 20892. |
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| Abstract: | Two classes of insulin-like growth factor I (IGF-I) cDNAs were isolated from an adult rat liver library using a human IGF-I cDNA probe. The two types of rat IGF-I cDNA differed by the presence or absence of a 52-base pair insert which altered the derived C-terminal amino acid sequence of the E peptide, but not the 3'-untranslated region or the sequence coding for the mature IGF-I protein. When probes derived from these cDNA clones were hybridized to Northern blots of rat mRNA, specific bands of 8.6, 2.1, and 1.0-1.4 kilobases were seen. Hybridization to poly(A)+ RNA from various tissues from GH-treated and control rats demonstrated an increase in IGF-I mRNA due to GH treatment in all tissues examined. |
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