Regulation of Insulin- and Insulin Receptor-Encoding mRNAS in Rainbow Trout, Oncorhynchus Mykiss

Abstract

In this work, rainbow trout were used as a model system to examine the regulation of insulin (INS)- and insulin receptor (IR)-encoding mRNA expression profiles. INS- and IR-encoding mRNAs were isolated, cloned, and sequenced; and shown to be differentially expressed within and among multiple tissue types. Regulation was examined through various nutritional and hormonal treatments (in vivo and in vitro). A real-time quantitative-PCR assay was developed to measure the respective levels of mRNA expression. Fasting, growth hormone (GH), and somatostatin (SS) differentially regulated INS and IR mRNAs within selected tissues, in vivo. Glucose, GH, SS, and insulin-like growth factor-1 (IGF-I) differentially regulated INS and IR mRNAs within selected tissues, in vitro. The results of this dissertation research display the identification and differential regulation of multiple INS- and IR-encoding mRNAs and suggest that independent mechanisms may serve to regulate the various isoforms in a tissue-specific manner. Future studies are also suggested.