Characterisation of the expression and post‐translational processing of the preprotachykinin‐I gene and the regulated release of tachykinins by the RINm5F cell‐line

Normal transcription and postranslational processing of the preprotachykinin (PPT)-I gene and regulated release of substance P and neurokinin A by the rat pancreatic endocrine cell-line, RINm5F, has been demonstrated, using radioimmunoassays (RIAs), reversed-phase (rp)HPLC and Northern blot analysis. This is the first stable cell-line found to express the PPT-I gene and provides an opportunity for investigating PPT-I gene expression and tachykinin biosynthesis. RIN5mF cells are a model for the pancreatic beta-cell, which is not known to exhibit PPT-I gene expression which may, therefore, be a feature of the transformed state of these cells. These data may imply that the tachykinins are important in pancreatic islet embryogenesis.