Dihidrotestosteroon

Dihidrotestosteroon, commonly abbreviated as DHT, is a potent androgenic steroid hormone that is produced from testosterone through the action of the enzyme 5α-reductase. It binds to the androgen receptor with higher affinity than testosterone and is a key driver of androgen signaling in many tissues.

Biosynthesis and distribution occur mainly in androgen target tissues such as the prostate, skin (including scalp hair follicles), and liver. In these tissues, testosterone is converted to DHT by 5α-reductase type 1 and type 2. Because of local production, tissue concentrations of DHT can be high even when circulating levels are relatively low.

Functions of DHT include roles in the development of male external genitalia during fetal life, as well as the maintenance of male secondary sexual characteristics during puberty and adulthood. It influences prostate growth, facial and body hair, and sebaceous gland activity. DHT operates by activating the androgen receptor to regulate gene expression.

Clinical relevance centers on conditions influenced by DHT levels. Excessive DHT is associated with androgenetic alopecia (male pattern baldness) and benign prostatic hyperplasia. Deficiency in DHT signaling can contribute to undervirilization in genetic males. Pharmacological inhibition of 5α-reductase (for example with finasteride or dutasteride) lowers DHT levels and is used to treat BPH and hair loss; potential side effects include reduced libido and sexual dysfunction.

Metabolism of DHT primarily involves inactivation to less active metabolites, such as 3α-diol and 3β-diol, via 3α-hydroxysteroid dehydrogenase, followed by excretion. DHT is not aromatizable to estrogen.