Effects of Ninjin-to on Levels of Brain-Gut Peptides (Motilin, Vasoactive Intestinal Peptide, Gastrin, and Somatostatin) in Human Plasma

We examined the effects of Ninjin-to, a traditional Chinese (Kampo) medicine, on the levels of brain-gut peptides (motilin, vasoactive intestinal peptide (VIP), gastrin, and somatostatin) in plasma from healthy subjects. A single oral administration of Ninjin-to, at a dose of 6.0 g, caused significant increases in plasma motilin levels at 40 to 90 min and somatostatin levels at 20 to 90 min, compared with a placebo treated group. Transient elevations of gastrin levels in the placebo group were inhibited by administration of Ninjin-to, but the medicine did not alter the levels of VIP. In conclusion, these results suggest that pharmacological effects of Ninjin-to on gastrointestinal functions closely relate to changes of motilin, gastrin, and somatostatin-immunoreactive substance levels in human plasma.