The activation of serotonin receptors by tryptamine induces hyperinsulinemia in mice.

The effects of tryptamine on serum insulin levels were investigated. Tryptamine induced an apparent increase in serum insulin levels in mice. The elevation in insulin elicited by tryptamine was potently antagonized by the 5-HT1 and 5-HT2 receptor antagonist, methysergide, but partially reduced by the 5-HT2 receptor antagonist, ketanserin. However, the 5-HT3 receptor antagonist, ICS 205-930, was without effect. These results indicate that both 5-HT1 and 5-HT2 receptors are involved in the tryptamine-induced increase in insulin levels.