Prostate gland benign hyperplasia

O The lower urinary tract symptoms and signs of benign prostatic hyperplasia are due to static, dynamic, or detrusor factors. The static factor refers to anatomic obstruction of the bladder neck caused by an enlarged prostate gland. The dynamic factor refers to excessive stimulation of a-adrenergic receptors in the smooth muscle of the prostate, urethra, and bladder neck. The detrusor factor refers to irritability of hypertrophied detrusor muscle as a result of long-standing bladder outlet obstruction. 

Finasteride is a selective inhibitor of 5-alpha-reductase. It thereby reduces prostatic concentrations of dihydrotestosterone and so reduces prostatic size (6,7,8). It is therefore used to treat benign prostatic hyperplasia (9,10,11,12) and in the prevention and treatment of prostate cancer (13). It is poorly effective in patients with prostatic obstruction and small prostate glands (14), but in patients with glands larger than 40 ml it produces significant symptomatic improvement. 

Contraction of the smooth muscle of the prostate gland, prostatic urethra, and bladder neck is also mediated by ai-adrenoceptors, with a, being predominant, and blockade of these receptors relaxes the tissue. For this reason the quinazoline a,-antagonists doxazosin (42), prazosin (43), and terazosin (44) have also found use in treatment of benign prostatic hyperplasia (BPH). However, prazosin. 

Quinazolines. Prazosin (43), the first known selective a,-blocker, was discovered in the late 1960s (92) and is now one of a small group of selective a,-antagonists, which includes two other quinazoline antihypertensives, terazosin (44) (25, 93) and doxazosin (42). The latter, along with tamsulosin (24), was discovered to block a,-receptors in the prostate gland and alleviate the symptoms of benign prostatic hyperplasia (BPH). 

Benign prostatic hyperplasia—Nonmalignant enlargement of the prostate gland in elderly men. 

Prazosin is an antihypertensive agent, as are terazosin and doxazosin. The latter two were subsequently discovered to block ai-receptors in the prostate gland and alleviate the symptoms of benign prostatic hyperplasia (BPH) (see Chapter 45). The more recently developed tamsulosin and alfuzosin are more selective for the subtype of ai-adrenoceptor found in the prostate gland, aiA, over those found in vascular tissue. Thus, tamsulosin and alfuzosin are first-line drugs for the treatment of BPH and have no utility in treating hypertension. They have fewer cardiovascular side effects than terazosin and doxazosin ... 

Benign Prostatic Hyperplasia Enlargement of the prostate gland. 

Finasteride inhibits 5a-reductase, the enzyme converting T. into dihydrotestosterone (DHT). Thus, the androgenic stimulus is reduced in those tissues in which DHT is the active species (e.g., prostate). T.-dependent tissues or functions are not or hardly affected (e.g., skeletal muscle, negative feedback inhibition of gonadotropin secretion, and libido). Finasteride can be used in benign prostate hyperplasia to shrink the gland and, possibly, to improve micturition. 

Urinary glucuronides of testosterone and dihydrotestosterone from patients with benign prostate hyperplasia were analysed using on-line SPE-LC coupled to ion-trap MS operated in negative-ion ESI-MS [72]. Because DHEA, excreted by the adrenal gland, is converted into testosterone and subsequently into dihydrotestosterone, it can be involved in the growth of prostate cancer. In order to study this in more detail, an LC-MS method was developed for the simultaneous determination of... 

Observations that hermaphroditic children who ultimately turned male were genetically deficient in 5a-reductase led to the idea that competitive inhibitors of this enzyme would greatly decrease levels of dihydrotestosterone. This might in turn reduce the oversize gland in the common affliction of elderly men called benign prostatic hyperplasia (BPH), and avoid the usual therapy—surgery. The synthetic 4-azasteroid finasteride (Proscar) was introduced (1992) to treat BPH in a defined patient population. 

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