Norepinephrine metabolism in the rat brain following acute and chronic administration of thyrotropin releasing hormone

Synthetic thyrotropin releasing hormone (TBH) was administered to albino rats in order to determine the effects of this drug on norepinephrine-H3 metabolism in the brain. With the possible exception of a slight enhancement of release, acute or chronic administration of TRH had little effect on the disposition and metabolism of norepinephrine-H3 in rat brain. In addition, no significant changes were found in brain levels of endogenous norepinephrine, serotonin or dopamine following the injection of TRH. Thus, little evidence was found to support a possible relationship between the reported clinical antidepressant activity of TRH and its effects on norepinephrine metabolism in brain.