Glucocorticoids (steroids) can be used as a treatment for asthma and inflammatory conditions whereas NSAIDs are used to treat inflammation but have no use in asthma treatment. Which of the following statements most accurately describes why these treatments differ?
Correct Answer: Steroids block production of all eicosanoids, whereas NSAIDs only block production of thromboxanes and prostaglandins.
Description: The eicosanoids (prostaglandins, thromboxanes, and leukotrienes) are synthesized from polyunsaturated fatty acids released from membrane phospholipids by phospholipase A2 . Glucocorticoids inhibit phospholipase A2 and thereby block production of all eicosanoids. NSAIDs inhibit COX, which converts arachidonic acid to prostaglandins and thereby block prostaglandin production. Because thromboxanes are derived from prostaglandins, NSAIDs also indirectly block thromboxane production. Leukotrienes, however, are produced from arachidonic acid by a different pathway (lipoxygenase) than prostaglandins and thereby are not blocked by NSAIDs. Leukotrienes are involved in asthma, so leukotriene inhibitors can be used to treat asthma.
Category:
Biochemistry
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