Gastric trefoil peptides work on the night shift
Trefoil peptide TFF2 secretion has a circadian rhythm with highest concentrations detected during the night sleep, suggesting repair of gastric mucosa occurs at this time.
Trefoil peptides are small proteins secreted by the gastric antral and pyloric glands and are found in high concentrations around sites of gastric ulceration. TFF2 stimulates cell motility and is probably the principal cytoprotective trefoil peptide in the stomach. In May Gut Semple and colleagues from the University of Newcastle upon Tyne found a dramatic diurnal variation of the TFF2 concentration in gastric juice, perhaps partly explaining the cytoprotective effects of a good night sleep.
Using quantitative western transfer analysis Semple et al measured TFF2 proteins in the gastric juice of 12 normal volunteers during a normal 24h cycle. They collected samples every 2h and found that the mean concentration of TFF2 was lowest in the early evening (0.29 μg/ml), increased gradually during the evening, and rose sharply during the night to reach 7.9 μg/ml (Gut 2001,48:648-655). The ratio of glycosylated to non-glycosylated TFF2 was also higher during the night than in the afternoon.
The increase in TTF2 is probably designed to facilitate repair of gastric mucosa at night. These results could suggest that missing out on a good night's sleep through partying, long haul travel or shift work may increase the risk of gastric ulcers.