TRH's male repro phys; 4.1 Flashcards
Where are sperm produced?
Seminiferous tubules
What are spermatogonia? Where are they?
Sperm stem cells
The epithelium of seminiferous tubules
What are spermatocytes? Where are they?
Sperm in the process of maturing
The epithelium of seminiferous tubules
What do Sertoli cells do? Where are they?
Sertoli cells form a blood-testes barrier, provide nutrients to differentiating sperm, and secrete an aqueous fluid into the lumen of the seminiferous tubules
The epithelium of seminiferous tubules
What kind of receptor are prevalent on Sertoli cells?
FSH receptor
can think of as the male granulosa cells…even secrete inhibin
What do Leydig cells do?
Synthesize and secrete testosterone (95% of the body’s testosterone…other 5% from adrenals)
(can think of as the male version of theca cells…even have LH receptors)
What is andropause?
Androgen deficiency with aging (decrease in testicular function)
What are the symptoms of andropause?
ED
Weight gain d/t metabolism shifts
Reduced activity
Gynecomastia
What hormones will be high with andropause?
Gonadotropins (FSH/LH)
no feedback inhibition
What is dihydrotestosterone (DHT)?
A potent androgen
What enzyme converts testosterone to DHT?
5α reductase
What is Sex Hormone Binding Protein (SHBP) called in Sertoli cells (where it is also made)?
Androgen binding globulin
What are some of the hormonal functions of androgen?
Promote health/function of: Seminal vesicle Prostate Genital tract External genitalia Hair growth patterns Voice change
What anabolic effects do androgens have?
Positive nitrogen balance
Bone growth and epiphysis closure
Sodium and water retention
What is methyl testosterone?
Testosterone replacement therapy
What is a toxicity of methyl testosterone?
Hepatotoxicity
What is oxandrolone?
Anabolic steroid (DHT derivative)
Does oxandrolone have the same hepatotoxicity as methyl testosterone?
Not really…low risk of hepatotoxicity
What is flutamide?
Non-steroidal androgen receptor antagonist
What does flutamide do?
Causes medical castration
When is flutamide used?
Flutamide is used in advanced prostate cancer
What are the side effects of flutamide?
Gynecomastia
Hepatotoxicity
What are gonadorelin and leuprolide?
Non-pulsatile GnRH (LHRH) agonists
What is gonadorelin used for?
Functional assessment of gonadal response
What is leuprolide used for?
Castration for cancer patients
How does leuprolide work?
Continuous administration → ↑ of LH and FSH → ↑ T → 10 day desensitization of the pituitary and suppression of LH and FSH
What are degarelix, ganirelix, and cetrorelix?
Non-pulsatile GnRH antagonists
What is degarelix used for?
Castration for advanced prostate cancer/BPH
What are ganirelix and cetrorelix used for?
Blocks premature LH surge in females
What is finastride?
5α-reductase inhibitor
What is finastride used for?
Male pattern baldness and BPH
So in a nutshell, when should GnRH agonists/antagonists be used?
When the goal is to shut down the hypothalamic-pituitary-gonadal axis
What should be used to reduce androgen receptor signaling in the prostate gland?
Androgen receptor agonists; and/or 5α-reductase inhibitors; and/or GnRH antagonists
What drug is a PDE-5 inhibitor?
Sildenafil
What is the MoA of sildenafil?
Prevents degradation of cGMP
