Nutritionally-induced changes in hepatic insulin-like growth factor I (IGF-I) gene expression in rats.
We have used [32P]-labeled human and mouse IGF-I cDNA probes to identify three hepatic IGF-I transcripts (8.0, 1.8 and 1.1 kilobase) in rats and to quantify nutritionally-induced changes. During fasting, the major (8.0 kilobase) transcript decreased progressively after 6 h, and at 30 h was only 39% as abundant as in the nonfasted control. Refeeding animals fasted 24 h caused a marked rise in the 8.0-kb mRNA by 6 h, and an 18-fold increase at 30 h. The two minor transcripts also appeared to behave in a similar manner. Serum IGF-I concentrations paralleled levels of the major hepatic transcript during periods of both fasting and refeeding, verifying the central role of nutrition in growth regulation.
D000818:Animals; D004435:Eating; D005215:Fasting; D005796:Genes; D007334:Insulin-Like Growth Factor I / Q000097:blood / Q000235:genetics*; D008099:Liver / Q000378:metabolism*; D008297:Male; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics* / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D013002:Somatomedins / Q000235:genetics*; D014158:Transcription, Genetic
D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I