leukotriene receptor antagonists and synthesis inhibitors, are a new class of anti-inflammatory drugs that have shown clinical efficacy in the management of asthma.
α-Naphthylisothiocyanate (ANIT) administration to rats results in periportal hepatic inflammation and injury. Glutathione (GSH) appears to be necessary for the liver injury to occur. The leukotrienes (LTs) are metabolites of arachidonic acid and potent mediators of inflammation that have been implicated in certain liver injury models. Inasmuch as GSH is a cofactor for the synthesis of cysteinyl-LTs and since inflammation is a prominent component of ANIT injury, we hypothesized that LTs are involved in producing the hepatic insult that results from ANIT administration. To test this hypothesis, rats were treated with one of several inhibitors of LT biosynthesis, A63162, Zileuton or MK-886. Each of these agents prevented the formation of LTB4 in Ca++ ionophore-stimulated whole blood from rats treated with the inhibitors. A63162 attenuated the hepatic parenchymal injury caused by ANIT and resulted in a modest decrease in ANIT-induced cholestasis. In contrast, neither Zileuton nor MK-886 attenuated liver injury. AT-125 (Acivicin) inhibits γ-glutamyl transferase (GGT), the enzyme that catalyzes the formation of LTD4 from LTC4. AT-125 pretreatment did not prevent ANIT-induced hepatic parenchymal insult. It did, however, ameliorate the cholestasis caused by ANIT. In conclusion, the partial protection afforded by A63162 and AT-125 likely results from, effects unrelated to the formation of LTs, since Zileuton and MK-886 inhibited LT synthesis without affording protection. The lack of protection by Zileuton and MK-886 in the face of LT synthesis inhibition suggests that LTs are not necessary for the expression of injury after ANIT administration.
Leukotrienes - biosynthesis and mechanisms of ..
Here we show that ER stress and chemotherapy induce leukotriene C4 (LTC4) biosynthesis by transcriptionally upregulating and activating the enzyme microsomal glutathione-S-transferase 2 (MGST2) in cells of non-haematopoietic lineage.
leukotriene antagonists - pictures, photos
Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Brönsted acid isomerize primary and secondary propargylic alcohols in good yields to provide enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride, in the presence of indium triflate and camphorsulfonic acid, gives the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity.
Leukotriene biosynthesis pathway
Leukotriene receptor antagonists, anti-IgE antibodies and monoclonal CD-4-molecules, as also soluble cytokine receptors are potential therapeutic options, the value of which currently remains unknown.
Leukotrienes are released from mast cells, basophils and eosinophils
Two types of leukotriene modifier - based medications have been developed: leukotriene inhibitors that interfere with the actual synthesis of leukotrienes, and leukotriene antagonists that block the action of leukotrienes by blocking leukotriene receptor sites.
Two leukotrienes inhibitors are available: once a day Singulair and twice a day Accolate.