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Enzymic Synthesis of Leukotriene B 4 in Guinea Pig Brain
Author(s) -
Shimizu Takao,
Takusagawa Yutaka,
Izumi Takashi,
Ohishi Nobuya,
Seyama Yousuke
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb05698.x
Subject(s) - arachidonic acid , guinea pig , leukotriene , leukotriene c4 , enzyme , biochemistry , leukotriene b4 , cytosol , chemistry , arachidonate 5 lipoxygenase , leukotriene d4 , lipoxygenase , microsome , endocrinology , medicine , biology , receptor , inflammation , immunology , antagonist , asthma
Leukotriene B 4 [5( S ), 12( R )‐dihydroxy‐6,14‐ cis‐ 8,10‐ trans ‐eicosatetraenoic acid] was obtained from endogenous arachidonic acid when slices of the guinea pig brain cortex were incubated with the calcium ionophore A 23187. Enzymes involved in its synthesis, arachidonate 5‐lipoxygenase [arachidonic acid to 5( S )‐hydroperoxy‐6‐ trans ‐8,11,14‐ cis ‐eicosatetraenoic acid and subsequently to leukotriene A 4 ] and leukotriene A 4 hydrolase (leukotriene A 4 to B 4 ), were present in the cytosol fraction. Arachidonate 5‐lipoxygenase was Ca 2+ ‐dependent, and was stimulated by ATP and the microsomal membrane, as was noted for the enzyme from mast cells. The lipid hydroperoxides stimulated 5‐lipoxygenase by four‐ to sixfold. The leukotriene A 4 hydrolase activity was rich in brain, and the specific activity (0.4 nmol/min/mg of protein) was much the same as that of guinea pig leukocytes. High activities of these enzymes were detected in the olfactory bulb, pituitary gland, hypothalamus, and cerebral cortex. Since leukotriene B 4 is enzymically synthesized in the brain, possible roles related to neuronal functions or dysfunctions deserve to be examined.