Peripherally administered serotonin induces hyperglucagonemia in mice.

Peripherally administered serotonin (5-HT) induced a marked increase in the plasma glucagon level in mice. The hyperglucagonemic effects of 5-HT were completely antagonized by methysergide, ketanserin and ritanserin which have a high affinity for 5-HT2 receptors. However, the 5-HT3 receptor antagonist ICS 205-930 and MDL 72222 were without effect. These findings suggest that the activation of the peripheral 5-HT2 receptor induces the increase in plasma glucagon level and that these receptors may play a role in the release of glucagon.