Rikkunshi-to Raises Levels of Somatostatin and Gastrin in Human Plasma

Rikkunshi-to, a traditional Chinese (Kampo) medicine, has been used to treat chronic hypofunctions of the gastrointestinal tract. The effects of Rikkunshi-to on the plasma levels of gut-regulated peptide (somatostatin, motilin, gastrin, and vasoactive intestinal peptide (VIP)) levels were studied in healthy subjects. A single oral administration of Rikkunshi-to caused significant increases in plasma somatostatin and gastrin levels at 60 to 240 min compared with a placebo group. On the other hand, this medicine showed no effects on motilin and VIP levels. In conclusion, these results might indicate that the pharmacological action of Rikkunshi-to is closely related to changes in somatostatin- and gastrin-immunoreactive substance levels.