What is the function of the enzyme 5 alpha-reductase in steroid metabolism?
5α-Reductase is a membrane bound enzyme that catalyzes the NADPH dependent reduction of double bonds in steroid substrates to increase potency.
How are steroid hormones metabolized in the body?
Many tissues, but mainly the liver, metabolize the steroid hormones to physiologically inactive products that are voided mainly in the urine, though some are also eliminated via the bile and, ultimately, the feces. Diagnosis of endocrine abnormalities may be assisted by analysis of urinary steroids.
What enzyme is responsible for converting testosterone to DHT?
Testosterone converts to DHT by the action of the 5 alpha-reductase enzyme at these target tissues.  This isolated synthesis at a specific target tissue makes DHT primarily a paracrine hormone.
How steroid hormones are synthesized?
The steroid hormones are synthesized in the adrenal cortex, the gonads, and the placenta; are all derived from cholesterol and many are of clinical importance. Steroid hormones are synthesized in the mitochondria and smooth endoplasmic reticulum.
What does 5-alpha-reductase inhibitor do?
5-alpha-reductase inhibitors are a group of drugs that are used in the treatment of an enlarged prostate gland (benign prostatic hyperplasia) and male pattern hair loss. Drugs in this class are finasteride (marketed as Proscar [finasteride 5 mg] and Propecia [finasteride 1 mg]) and dutasteride (marketed as Avodart).
Where is 5-alpha-reductase found 2?
The conversion of testosterone to dihydrotestosterone is catalyzed by the enzyme 5α-reductase (5AR), which exists in 2 forms: Type 1 and Type 2, both of which are found in the prostate.
How are steroid hormones inactivated and excreted?
The main site of peripheral steroid inactivation and catabolism is the liver, but some catabolic activity also occurs in the kidneys. Inactive hormones are mainly eliminated as urinary (mostly conjugated) metabolites. Usually, steroids are eliminated once they have been inactivated (i.e., they are not ” recycled “).
Which steroids are DHT derivatives?
- Marketed. Bolazine (an azine dimer prodrug of drostanolone) Drostanolone (2α-methyl-DHT) Epitiostanol (2α,3α-epithio-DHT)
- Never marketed. 1-Testosterone (dihydroboldenone; δ1-DHT) Mesabolone (a 17-ether prodrug of δ1-DHT) Prostanozol (a 17-ether prodrug of 17α-demethylstanozolol)
Where is 5-alpha-reductase found?
The conversion of testosterone to dihydrotestosterone is catalyzed by the enzyme 5α-reductase (5AR), which exists in 2 forms: Type 1 and Type 2, both of which are found in the prostate. Type 1 is produced primarily in liver and skin and is carried to the prostate via the systemic circulation.
Where are lipids and steroids synthesized in the cell?
The endoplasmic reticulum (ER)
The endoplasmic reticulum (ER) is the main site for lipid synthesis.
When are 5-alpha-reductase inhibitors indicated?
The FDA currently has two approved indications for 5-alpha-reductase inhibitors. These conditions include benign prostate hyperplasia (BPH) and androgenic alopecia (male pattern hair loss). While not approved by the FDA, clinicians have used 5-alpha-reductase inhibitors in the management of hirsutism.