Changes in expression levels of neurotensin precursor and receptor mRNA in chicken intestinal tissues and liver during late embryonic and early posthatching development.

Neurotensin is a tridecapeptide that has multiple functions as a neurotransmitter and as a circulating hormone. Neurotensin and its related peptide, LANT6, have been isolated in the chicken, but the mRNA encoding these peptides has not been identified. In this study, we first cloned the cDNA for the chicken neurotensin precursor mRNA from the duodenum and characterized its primary structure and then investigated tissue expression patterns of neurotensin precursor and receptor mRNA. The cDNA encoded a protein of 495 amino acids that contains the sequences of chicken neurotensin and LANT6 in the C-terminal region. Real-time PCR analysis showed that the neurotensin precursor mRNA is preferentially expressed in intestinal tissues, such as the duodenum, jejunum, ileum, and colon/rectum, with temporal increases during the hatching period. The expression levels of neurotensin receptor 1 mRNA were relatively higher during the late embryonic period compared with the posthatching period in the duodenum and jejunum, whereas the expression levels were higher in the colon/rectum during the posthatching period. In the liver, the expression levels of neurotensin receptor 1 were markedly increased during the early posthatching period. These results suggest that chicken neurotensin is involved in the regulation of gastrointestinal and hepatic functions, especially during the hatching period.