DISTRIBUTION AND DEVELOPMENTAL PATTERN OF NEUROMEDIN-U EXPRESSION IN THE RAT GASTROINTESTINAL-TRACT

This study has quantified, for the first time, the relative levels of neuromedin U (NmU) mRNA in the rat gastrointestinal tract using Northe rn blot analysis. NmU message was detected in all regions of the gastr ointestinal tract from the oesophagus to the rectum. The greatest leve ls were found in the duodenum and jejunum, the principal sites for abs orption, which were 2.5- and 3-fold respectively above ileal levels. Q uantification of NmU mRNA and peptide contents in the duodenum, jejunu m and ileum during postnatal development of the rat showed message and peptide levels to be greater in the maturing rat than in neonates. Me ssage levels in the duodenum, jejunum and ileum showed 14-, 7- and LC- fold increases respectively between 1 and 56 days after birth, whilst the corresponding peptide levels in the duodenum, jejunum and ileum sh owed 33-, 14- and 25-fold increases respectively. Food deprivation cau sed a small, but significant, decrease in message levels in the jejunu m and colon, but there was no change in the duodenum or ileum. This sh ows that the presence of food has little effect on NmU mRNA levels in the gut.