Abstract
1. From the results now presented, serotonin-induced hyperlactacidemia occurs without participation of other endocrine factors.
2. Serotonin directly reduced the lactate utilization of perfused liver.
3. Eviscerated rats developed hyperlactacidemia in response to minute dose of serotonin.
4. It may be concluded that an increase of blood lactate caused by serotonin is due to both enhancement of extrahepatic production of lactate and retardation of hepatic utilization.
