Pharmacology of Androgens Flashcards
What are the 3 androgens?
- Testosterone
- Androstenedione
- Dehydroepiandrosterone (DHEA)
What is the main difference between testosterone and estradiol?
- methyl group on testosterone’s 4 ring structure
What produces androgens?
- testis= leydig cells
- adrenal glands
- ovary= theca cells
Can production of testosterone come from progesterone?
YES via cytochrome P450 to androstenedione and then to testosterone.
To what is testosterone metabolized in the prostate?
- 5-alpha dihydrotestosterone (DHT) via 5 alpha reductase.
* testosterone is unchanged in other tissues (muscle, kidney…)
What is the most potent androgen required for sex development?
- DHT
What regulates androgen production?
- LH from the anterior pituitary
* receptors for LH are found on Leydig cells in the testes.
Where else are androgens produced?
- adrenal cortex
What regulates sertoli cells in the testes?
- FSH from the anterior pituitary
What stimulates the adrenal glands to secrete cortisol and sex steroids?
- adrenocorticotropin
What is sex hormone binding globulin (SHBG)?
- serum glycoprotein derived from liver that binds testosterone in circulation
What INCREASES sex hormone binding globulin (SHBG)? (aka less free testosterone in the circulation)
- estrogens
- thyroxine
What DECREASES sex hormone binding globulin (SHBG)? (aka more free testosterone in circulation)?
- androgens
- GH
- insulin
What are the pharmacologic actions of androgens?
- sperm production
- erythropoiesis
- positive nitrogen balance
- growth/development of hair, bone, and muscle.
*** What is the major use for androgens?
- replacement therapy in men who have reduced testosterone production (primary testicular insufficiency).
What are the available IM injection testosterones?
- cypionate= 2-3 weeks
- enanthate= 2-3 weeks
- propionate= 1-3 days
Where is a testosterone transdermal patch applied?
- scrotal skin bc it’s thinner than other epidermis.
What are the actions of anabolic steroids (synthetic derivatives of testosterone)?
- increase muscle mass
- increase physical performance
- increase linear growth (children)
** What is OXANDROLONE (anavar; oxandrin)?
- anabolic steroid used for PRIMARY and SECONDARY testicular failure.
- increases expression of secondary sex characteristics
*** What is secondary testicular failure?
- insufficient stimulation of testes by pituitary gonadotropins (hypogonadotropic hypogonadism).
What is an ADR of using androgen therapy to increase height of short children?
- premature closure of epiphyseal plates and virilization.
* best to combine with GH
What are the therapeutic uses of androgens?
- treatment of aplastic anemia (erythropoiesis)
- inoperable breast cancer
- postpartum breast pain
- malnutrition
** What is DANAZOL (danocrine)?
WEAK androgen used for the treatment of:
- endometriosis
- fibrocystic breast disease
- PMS
What was the result of using testosterone supplementation to treat men with multiple sclerosis (MS)?
- improvement in cognitive performance
- slowing of brain atrophy
- increase in lean body mass
- potential neuroprotective effects in men with relapsing-remitting MS
