question - GnRH analog - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
USMLE Articles
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam

Thread Tools Search this Thread Display Modes
Old 10-30-2010
mtoi's Avatar
USMLE Forums Scout
Steps History: Not yet
Posts: 71
Threads: 30
Thanked 52 Times in 29 Posts
Reputation: 62
Drug question - GnRH analog

PATIENT PROFILE - 59 yo male with 2 month hx of back pain, not relieved with over-the-counter pain relievers. Pain worse at night and interferes with sleep, tenderness at lumbar vertebrae, digital rectal exam reveals enlarged and firm prostate.
Rx – you start him on leuprolide
QUESTION – which of the following changes in testosterone(T) and dihydrotestosterone (DHT) levels are most likely to occur?
A no change
B discordant decrease in DHT levels
C steady decrease in T and DHT
D first discordant increase, then discordant decrease in DHT level
E first concordant increase , then concordant decrease in T and DHT levels

please expalin your answer too
Reply With Quote Quick reply to this message

Old 10-31-2010
mtoi's Avatar
USMLE Forums Scout
Steps History: Not yet
Posts: 71
Threads: 30
Thanked 52 Times in 29 Posts
Reputation: 62

no one attempted this question after 80 views
the objective of these questions is to self-study for me and i have noticed that you folks know a whole lot more than me
i will request you folks to share your knowledge with me please

Ans – pulsatile release of gonadotropin-releasing hormone (GnRH) from hypothalamus is the natural state of human functioning causing release of gonadotropins from pituitary that in turn stimulates release of testosterone in man
Testosterone is converted to DHT in target tissues by enzyme 5-alpha reductase
Alternately, if GnRH levels are constantly elevated rather than pulsed, the secretion of LH and FSH from pituitary will be suppressed
A number of GnRH analogs, such as leuprolide, have been generated by amino acid substitutions-alterations that allow longer half lives and increased activity
Leuprolide is a long-acting GnRH analog that causes continuous GnRH activity
The result is ultimately suppression of pituitary-gonadal axis for the duration of Rx, although there is a brief period of initial stimulation, sometimes called “start up flare”
An increase in gonadotropin levels during the initial flare up period causes increase in both T and DHT levels (concordant increase)
Soon the start up flare burns out and both T and DHT are typically suppressed to castrate levels
These very low levels of androgens are useful for Rx of androgen-dependant cancers, such as prostate
Reply With Quote Quick reply to this message
The above post was thanked by:
ashishkabir (10-31-2010), dr_lizard (09-04-2011), Hassan92 (07-23-2016), heights (10-31-2010), Pixie (10-31-2010), step1an (10-31-2010)
Old 10-31-2010
USMLE Forums Guru
Steps History: 1 + CK
Posts: 373
Threads: 30
Thanked 372 Times in 159 Posts
Reputation: 382

Thanks for the question & the nice explanation.
Knowing is not enough; we must apply.
Willing is not enough; we must do.
Reply With Quote Quick reply to this message


Pharmacology-, Step-1-Questions

Quick Reply

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Where you live. Leave blank if you don't want to tell.


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
question help: diabetic foot related question dezirablize USMLE Step 2 CK Forum 5 01-15-2015 02:42 PM
Continuous GnRH Yallah USMLE Step 1 Forum 7 11-01-2010 01:40 AM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)