Regulation of insulin-like growth factor I gene expression by growth hormone.
Recombinant clones containing exon 3 of the insulin-like growth factor I (IGF-I) gene were isolated from a mouse genomic library. These sequences were used to generate an RNA probe, which was used in a solution hybridization assay to quantitate IGF-I mRNA in various murine tissues as a function of growth hormone status. The liver is the major site of IGF-I synthesis and the level of IGF-I mRNA is regulated about 10-fold by growth hormone in the growth hormone-deficient lit/lit mouse. Nuclear run-on assays were used to show that growth hormone regulation is manifested in part at the transcriptional level. Growth hormone also affects the size distribution of hepatic IGF-I mRNAs. Pancreas showed the highest non-hepatic expression, but every tissue analyzed contained some IGF-I mRNA. Expression was not growth hormone-dependent in most non-hepatic tissues.
Mathews
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Norstedt
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Palmiter
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D000818:Animals; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D051379:Mice; D008817:Mice, Mutant Strains; D012333:RNA, Messenger / Q000235:genetics; D013002:Somatomedins / Q000235:genetics*; D013997:Time Factors; D014018:Tissue Distribution
D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone