The prostate is a small, walnut-sized gland located just below the bladder, surrounding the urethra. Its primary function is to produce fluid that makes up part of semen, which helps nourish and transport sperm. Dihydrotestosterone (DHT) is a potent androgen that promotes the development and maintenance of male characteristics. While DHT is necessary for the prostate’s normal growth throughout life, its continued activity in later years is strongly linked to the gland’s enlargement.
How Testosterone Becomes Dihydrotestosterone
Testosterone is the precursor hormone that the body uses to synthesize DHT. This conversion process is catalyzed by an enzyme called 5-alpha reductase (5-AR). The enzyme is present in various tissues, including the liver, skin, hair follicles, and the prostate gland. Once converted, DHT is significantly more potent than testosterone. It binds to androgen receptors inside the prostate cells with a much higher affinity, acting as an amplified signal for growth.
Although DHT is found in the bloodstream, the majority of its production happens locally within the prostate tissue. In the prostate, the concentration of DHT can be five to ten times higher than that of testosterone. This localized and potent activity ensures the prostate receives a powerful growth signal, regulating the gland’s size and function.
The Role of DHT in Prostate Enlargement
The continuous presence of DHT is a primary driver of the condition known as Benign Prostatic Hyperplasia (BPH), or non-cancerous prostate enlargement. While DHT is responsible for the prostate’s normal development and size maintenance, its persistent stimulation of cell growth over decades leads to an excessive accumulation of epithelial and stromal cells. This long-term stimulation disrupts the normal balance between cell proliferation and programmed cell death, causing the gland to steadily increase in volume.
As the prostate enlarges, it presses inward on the urethra, which runs through the center of the gland. This compression can lead to various lower urinary tract symptoms. These often include difficulty initiating urination, a weakened urine stream, incomplete bladder emptying, and an increased frequency or urgency of urination, especially at night.
The role of DHT in BPH is different from its role in prostate cancer. DHT is directly involved in the development and progression of BPH by stimulating cell growth and tissue accumulation. While androgens are necessary for prostate cancer to grow, the link between DHT and cancer initiation is more complex and less direct than its role in BPH. High DHT levels drive the volume increase in BPH, which is a non-malignant condition.
Medications That Target DHT Production
The central role of DHT in BPH has made the enzyme responsible for its production a target for medical intervention. A class of drugs called 5-alpha reductase inhibitors (5-ARIs) are used to treat prostate enlargement by directly interfering with the DHT pathway. These medications work by blocking the 5-alpha reductase enzyme, which reduces the amount of testosterone that can be converted into the more potent DHT.
By suppressing the synthesis of DHT, these inhibitors reduce the hormonal stimulation that drives prostate cell growth. The reduction in DHT levels causes the prostate gland to shrink over time, alleviating pressure on the urethra. This results in improved urinary flow and a reduction in BPH-related symptoms, such as frequent urination.
Because these drugs reduce the systemic levels of a powerful androgen, they can be associated with certain side effects. The most common side effects reported are related to sexual function, including a decrease in libido, erectile dysfunction, and problems with ejaculation. These effects occur because DHT is involved in the function of various tissues beyond the prostate, and reducing its overall concentration can impact these areas.