What describes the mechanism of action of dutasteride?

Dutasteride primarily functions by inhibiting the enzyme 5-alpha reductase, which plays a crucial role in the conversion of testosterone to dihydrotestosterone (DHT). This action is particularly significant in treating conditions influenced by DHT, such as benign prostatic hyperplasia (BPH). By blocking the activity of both type I and type II isoforms of 5-alpha reductase, dutasteride effectively reduces DHT levels in the body, leading to decreased prostate size and alleviation of urinary symptoms associated with BPH.

The other options involve different mechanisms that are not relevant to the actions of dutasteride, and they pertain to different types of receptors or enzymes that do not relate directly to its targeted inhibition of 5-alpha reductase. Understanding the specific enzymatic activity of dutasteride provides clarity on its therapeutic use and the rationale behind the management of prostate-related conditions.