Intravenous L-5-hydroxytryptophan in normal subjects: an interdisciplinary precursor loading study. Part IV: Effects on body temperature and cardiovascular functions.

In 14 healthy subjects the effect of a new soluble 1-5HTP ester (Ro 3-5940) in combination with a peripheral decarboxylase inhibitor on circulatory variables and body temperature was studied. The orthostatic adaptative functions were impaired while no consistent changes were observed in resting parameters. With the exception of an initial rise during infusion, measurements of oral temperature in the group as a whole showed no significant changes. However, if gender was considered, a long-lasting fall of temperature in males (N = 7) and rise in females (n = 6) was observed. The greatest difference between the hypothermic reaction in men and the hyperthermic reaction in women occured two hours after the end of infusion, at the same time where mood effects were most intense. The temperature findings support a modulatory function of central serotoninergic mechanisms in thermoregulation in man and emphasize the importance of sex specific factors in pharmacological studies.