The expression of insulin receptor mRNA was examined in rat pancreatic islet cells by single-cell reverse transcriptase (RT)–polymerase chain reaction (PCR). Single cells from disaggregated islets were individually isolated in a microcapillary pipet, and the β-cells were identified by amplification of the mRNA for insulin. We found that in single β-cells, the mRNA for the insulin receptor was also expressed. The fraction of single islet cells expressing both insulin receptor and insulin mRNAs corresponds closely to the fraction of β-cells in the disaggregated islet cell preparation. These results indicate that normal β-cells have the potential to express authentic insulin receptors. Immunohistochemical analysis was insufficiently sensitive for assaying insulin receptor protein; however, insulin receptor substrate 1 (IRS-1) was readily immunolocalized in islet β-cells. Since IRS-1 links several cell surface receptors, including those for insulin and IGF-I, to distal signal transduction pathways, our observations indicate that hormonal regulation of islet β-cells potentially involves the same signal transduction pathway that mediates insulin and growth factor signaling in peripheral insulin target tissue cell types.
Expression of Insulin Receptor mRNA and Insulin Receptor Substrate 1 in Pancreatic Islet β-Cells
Mark C Harbeck, Diane C Louie, Jennie Howland, Bryan A Wolf, Paul L Rothenberg; Expression of Insulin Receptor mRNA and Insulin Receptor Substrate 1 in Pancreatic Islet β-Cells. Diabetes 1 June 1996; 45 (6): 711–717. https://doi.org/10.2337/diab.45.6.711
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