Expression patterns of T1R3 in duodenal epithelial cells with some gastrointestinal hormone

tract (GI) (Hofer al ., 1996; Wu al ., 2002; Dyer al ., 2005; Grundy, 2005). They are additionally expressed in the stomach, small intestine – including the duodenum, and colon in mice and humans, with the exception of T1R2, which has not been detected in the mouse or human stomach or in the mouse colon (Bezençon et al ., 2007). There have been Summary. Recent studies have demonstrated that taste receptors, T1Rs and T2Rs, are expressed not only in taste buds but also in the gut. In the duodenum, it is thought that the secretion of secretin (S cells) and somatostatin (D cells) is stimulated by acid, that gastrin (G cells) and cholecystokinin (CCK) (I cells) are stimulated by proteins and amino acids, and that serotonin (EC cells) scretion is triggerd by mechanical stimulation sensing gut endocrine cells. We examined the expression of T1R3 in the duodenum by reverse transcription polymerase chain reaction (RT-PCR) and in situ hybridization. Double-label studies showed that approximately 50% of secretin positive cells (S cells) were coexpressed with T1R3, and approximately 33% of AADC positive cells (EC cells) were coexpressed with T1R3. On the other hand, T1R3 never colocalized with somatostatin (D cells), gastrin (G cells), or CCK (I cells). These results suggest that S cells may regulate the secretion of secretin, stimulated not only by acid but also by sweet substances and/or amino acids. of the circumvallate papilla (CV) and the duodenum, amplification products of the expected sizes were obtained with primer sets specific for T1R3 (610bp). On the other hand, amplification products were not obtained using RNA prepared from the epithelia of the duodenum without reverse transcription, which was performed as a negative control. β -actin was used as a control. suggest