GU Pharm

Question 1

Hypothalamic-Pituitary-Gonadal Axis

Answer 1

• Release of hypothalamic and anterior pituitary GnRH and FSH is pulsatile
• LH stimulates Leydig cells to produce testosterone
• Testosterone plus FSH stimulates Sertoli cells and sperm maturation
• Aromatase in sertoli cells also converts some of the T into estradiol

Question 2

What does continuous high concentrations of LH do?

Answer 2

Down regulates LH receptors in Leydig cells

Question 3

Drugs disrupting the HPG axis

Answer 3

GnRH analogs
Ant: Degarelix
Ag: Leuprolide, Nafarelin (nasal)
GnRH: Gonadorelin

Question 4

What androgen receptor antagonists are used with GnRH agonists

Answer 4

Bicalutamide or Flutamide

Question 5

What drugs disrupt androgen biosynthesis?

Answer 5

Abiraterone and Ketoconazole

Question 6

What enzyme CYP has both 17 ahydroxylahse and 17,20 lyase properties

Answer 6

CYP17

-Side effects are cortisol deprivation and aldosterone excess

Question 7

What do you administer in order to increase sperm counts in males?

Answer 7

HCG, it has a longer half life in circulation than LH and FSH and stimulates the Leydig cells to secrete testosterone
-Bears some resemblance to both LH and FSH

Question 8

Who gets secondary hypogonadism?

Answer 8

Males that are taking steroids

• They have a lot of testosterone on board but they also end up with a lot of estrogen
• This is also not a pulsatile application of the drug that creates the feedback inhibition

Question 9

Selective estrogen receptor modulator

Answer 9

Clomiphene

• Tricks the body into thinking that there isn’t estrogen there
• The hypothalamus is then stimulated to produce LHRH and restart natural testosterone production
• Long half life: loading dose is necessary

Question 10

Aromatase Inhibitors

Answer 10

Anastrozole

Letrazole