**Question:** Anti-inflammatory action of glucocorticoids is mainly due to

A. Inhibition of phospholipase A2
B. Suppression of transcription factors
C. Inhibition of prostaglandin synthesis
D. Inhibition of leukotriene synthesis

**Core Concept:** Glucocorticoids are a class of steroid hormones that possess anti-inflammatory, immunosuppressive, and anti-proliferative effects. They exert their actions by binding to glucocorticoid receptors (GR) present in the cytoplasm of cells.

**Why the Correct Answer is Right:** The correct answer, B. Suppression of transcription factors, highlights the key mechanism by which glucocorticoids exert their anti-inflammatory effects. Upon binding to their receptors, the formed glucocorticoid-receptor complex translocates to the nucleus, where it binds to specific DNA sequences called glucocorticoid response elements (GREs) in the promoter regions of target genes. This binding inhibits the transcription of several pro-inflammatory genes, leading to a decrease in inflammatory mediators such as cytokines, chemokines, and adhesion molecules.

**Why Each Wrong Option is Incorrect:**

A. Inhibition of phospholipase A2 (PLA2) is not the main mechanism of action for glucocorticoids in anti-inflammatory activity. Although glucocorticoids can inhibit PLA2, this is not the primary mechanism as it does not account for the whole spectrum of their anti-inflammatory effects.

C. Inhibition of prostaglandin synthesis is incorrect because glucocorticoids primarily act on transcription factors, not directly on enzymes involved in prostaglandin synthesis. Inhibition of prostaglandin synthesis may occur as a secondary effect, but it is not the main mechanism.

D. Inhibition of leukotriene synthesis is not the primary mechanism of action for glucocorticoids in anti-inflammatory activity. Although glucocorticoids can inhibit leukotriene synthesis, this is not the primary mechanism as it does not account for the whole spectrum of their anti-inflammatory effects.

**Clinical Pearl:** Recognizing the main mechanism of action of glucocorticoids is essential for understanding their anti-inflammatory effects. While glucocorticoids can have indirect effects on various enzymes, transcription factors, and cytokines, their primary mode of action lies in inhibiting the expression of pro-inflammatory genes through the glucocorticoid receptor binding to GREs, leading to a reduction in the synthesis of inflammatory mediators. This understanding is crucial for appropriate dosing and therapeutic use of glucocorticoids in managing inflammatory conditions.