Glossary · Mechanisms

Androgen receptor

Also called: AR.

Definition: The androgen receptor (AR) is a nuclear hormone receptor that binds testosterone and dihydrotestosterone (DHT) to mediate androgenic effects. AR is widely expressed including in muscle, bone, skin, brain, and reproductive tissues. SERMs and SERDs have analogs in the androgen-receptor world (e.g., spironolactone as antiandrogen).

Detailed definition

The androgen receptor (AR), encoded by the AR gene on the X chromosome, binds testosterone and the more potent metabolite dihydrotestosterone (DHT). It functions as a ligand-activated transcription factor in the nucleus, regulating androgen-responsive genes in target tissues. AR is widely expressed: skeletal muscle (driving anabolism), bone, sebaceous glands, hair follicles, brain (libido, mood), prostate, and many others. Mutations in AR cause androgen insensitivity syndromes. Antiandrogens (spironolactone, flutamide, enzalutamide) block AR for various clinical purposes — dermatologic, prostate cancer, others. In women, low-dose testosterone replacement for HSDD acts through AR; pellet doses produce supraphysiologic AR activation with predictable side effects.

Why it matters in menopause

For women starting low-dose testosterone for HSDD, the goal is to restore physiologic AR activation. Pellet doses overshoot, producing AR activation in male-range territory and predictable side effects.

Sources

External references: Wikipedia.

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