Activation of phosphatidylinositol turnover by neurotensin receptors in the human colonic adenocarcinoma cell line HT29.

Association of neurotensin to its receptor in HT29 cells increases the intracellular concentration of inositol phosphates. A rapid (20-30 s), transient stimulation of inositol trisphosphate (275% of the basal level) and inositol bisphosphate (420%) is first observed, followed by a slower, stable increase in inositol monophosphate (170%). Half-maximal stimulation of the three inositol phosphates was obtained with 50-100 nM neurotensin. These results indicate that neurotensin is able to regulate intracellular Ca2+ levels in HT29 cells by using inositol trisphosphate as a second messenger.