Regional distribution of leukotriene and mono-hydroxyeicosatetraenoic acid production in the rat brain. Highest leukotriene C4 formation in the hypothalamus.

The regional distribution of ionophore A23187-induced synthesis of leukotrienes and mono-hydroxyeicosatetraenoic acids in the rat brain in vitro was investigated. Pronounced differences in leukotriene C4 formation were observed, with the highest synthetic capacity in the hypothalamus. The formation of leukotriene C4 was about 12-times higher in the hypothalamus as compared to the cerebellum. This finding is in agreement with a possible neuroendocrine role for leukotriene C4. In contrast, the activity of leukotriene B4 synthesis was widely distributed without pronounced regional differences in the rat brain. Formation of 5-, 9-, 11-, 12- and 15-monohydroxyeicosatetraeonoic acid was detected in all regions. The major lipoxygenase product in the hypothalamus and thalamus was 5-hydroxyeicosatetraenoic acid, while other monohydroxyeicosatetraenoic acids predominated in the remaining regions tested.