Hypothermia induced in mice by enzyme-mediated depletion of serotonin

Summary Injection of a purified serotonin (and tryptophan)-degrading enzyme into mice produced a pronounced hypothermia when the mice were maintained at 22°C, but not at 30°C. Brain levels of serotonin and tryptophan were strikingly depleted, but concentrations of norepinephrine and dopamine remained unchanged.This investigation was supported by grants CA-18844 and CA-08748 awarded by the National Cancer Institute, DHEW. We thank Barbara Morelli and Margaret Costello for their technical assistance.