Effect of serotonin on hemolymph glucose regulation in the fresh water edible crab Oziotelphusa senex senex

One of the well known crustacean hormones is the crustacean hyperglycemic hormone (CHH). However, the mechanisms involved in the release of this hormone into circulation are poorly studied. The fresh water crabs Oziotelphusa senex senex were injected with serotonin and hemolymph glucose and CHH levels were determined. Injection of serotonin into intact crabs caused significant hyperglycemia in a dose-dependent manner. Administration of serotonin also caused a significant increase in the circulatory levels of CHH. In contrast, injection of serotonin did not cause any change in hemolymph glucose level in eyestalk ablated crabs. The results confirm that serotonin induced hyperglycemia was apparently mediated by the eyestalk hormone CHH.