L11 Androgens Flashcards
Describe the regulation of testosterone synthesis
When there is enough testosterone…
Negative feedback to hypothalamus
– Blocks GnRH (Gonadotropin-releasing hormone)
Negative feedback to Anterior Pituitary
– Blocks LH & FSH
Leydig cells are not stimulated to make testosterone - negative feedback loop
Describe the role of 5α-reductase in testosterone action
5α-reductase catalyzes the reaction of Testosterone → 5α-Dihydrotestosterone (major active androgen)
List the broad physiological effects of testosterone
- Responsible for many changes at puberty
- Growth-promoting properties
- Stimulation and maintenance of sexual function
- Stimulation of erythrocyte production
- Decrease in HDL level (“good cholesterol”)
List the growth-promoting physiological effects of testosterone
- Penile and scrotal growth
- Change in the skin (thicker and oilier)
- Pubic, axillary, and beard hair
- Deepening of the voice
- Skeletal growth followed by epiphyseal closure
- Increase in lean body mass → positive nitrogen balance
List the adverse effects of androgens for women
Hirsutism
Acne
Amenorrhea
Clitoral enlargement
Deepening of the voice
List the adverse effects of androgens
Acne
Sleep apnea
Gynecomastia (growth of breasts)
Azoospermia and testicular atrophy
Increased aggressiveness and psychotic symptoms
What is a contraindication for the use of testosterone for women?
Pregnancy
What age group can testosterone not be used for?
infants
What is a shared adverse effect of androgens?
Significant disturbances in sexual development
List the 5α-reductase inhibitors
Finasteride (Proscar®,Propecia®)
Dutasteride (Avodart®)
What is the clinical use for Proscar?
Benign Prostatic hyperplasia
What is the clinical use for Propecia?
Male pattern baldness
What are the clinical uses for Finasteride?
- Benign Prostatic hyperplasia (Proscar)
- Male pattern baldness (Propecia)
- Hirsutism in women
What are the clinical uses for Dutasteride?
- Benign Prostatic hyperplasia
- Male pattern baldness
What are the clinical uses for Avodart?
- Benign Prostatic hyperplasia
- Male pattern baldness
List the Steroidal androgen receptor antagonists
Cyproterone acetate (Androcur®)
Spironolactone (Aldactone®)
List the clinical uses for Cyproterone acetate
- Hirsutism in women
- Excessive sexual drive in men
List the clinical uses for Androcur
- Hirsutism in women
- Excessive sexual drive in men
List the clinical uses for Spironolactone
- Hirsutism in women
- Acne
List the clinical uses for Aldactone
- Hirsutism in women
- Acne
List the Non-steroidal androgen receptor inhibitors
flutamide (Eulexin®)
Enzalutamide (Xtandi®)
List the clinical uses for flutamide
Prostate cancer
List the clinical uses for Eulexin
Prostate cancer
List the clinical uses for Enzalutamide
Metastatic castration-resistant prostate cancer
List the clinical uses for Xtandi
Metastatic castration-resistant prostate cancer
Describe the action of 5α-reductase inhibitors
Block the conversion from testosterone to 5α-dihydrotestosterone (active androgen)
Describe the action of androgen receptor antagonists
Block the binding of endogenous androgens to the receptor or inhibit the activation of the receptors
