paganini
Forum Senior
Topics: 26
Posts: 153
|
In a 40 year old man with long standing hypogonadism resulting from total surgical castration for bilateral seminomas at the age of 17 years, the effectiveness of testosterone cypionate therapy can best be monitored by assessment of:
A. Plasma testosterone level
B. Plasma luteinizing hormone (LH) level
C. Plasma testosterone cypionate level
D. Change in muscle mass
E. Frequency of nocturnal erections
___________________
Mr. Physiology. An answering machine.
|
| cyra
Moderator
Topics: 29
Posts: 844
|
B.Plasma LH level
|
| paganini
Forum Senior
Topics: 26
Posts: 153
|
Correct answer is A. Plasma testosterone level
Try to explain why....
___________________
Mr. Physiology. An answering machine.
|
| step1mom
Forum Senior
Topics: 32
Posts: 64
|
as he didnot have congenital hypogonadism,so his hypothalamus pituitary axis is functioning.although they are not able to produce testosterone from the gonads which are not physically there.If we give exogenous testosterone,it should have a feed back effect on LH and there are then two answer options to the question
1...either we check lh levels which will fluctuate as exogenous testosterone given.
2...testosterone itself...as no testosterone is produced by his gonads so all testosterone in plasma will be the one that is exogenously given.ie option C
I dont agree with A as normal testosterone can neither be produces nor stimulated in this pt.I dont remember if testosterone is produced somewhere else in the males though..but it will not be stimulated by LH though.
|
| paganini
Forum Senior
Topics: 26
Posts: 153
|
Again answer is A.
You need to understand endocrine physiology and phamacology to get this question correct, maybe pathology but not necessarily. I must say it is a difficult question because we learned about testosterone negative feed back effect on LH in a normal person but not after a chronic disease.
First, what you need to know in pharmacology about this question is that testosterone esters are hydrolyzed by esterases in the blood as they are absorbed from oily depots in which are administered and, as a consequence, the esters themselvescan rarely be detected in blood. therefore, effectiveness of therapy agents such as testosterone cypionate can be monitored by measuring the plasma levels of testosterone itself. The physiology part of this question explain why LH levels (answer B) is not a good choice; in men with recent onset of hypogonadism, plasma LH levels should be suppresed into the normal range by testosterone but when LH levels have been high for many years, LH secretion becomes semiautonomous and may not return to the normal range for many months or years after the restoration of blood testosterone levels to normal. I personally think this is because testosterone regulates LH pulsatile secretion by negative feedback and maybe after many years of losing the negative feed back the LH is secreted conitinously and semiautonomously.the other answer: frequency of nocturnal erections, well this may or may not refflect plasma testosterone levels on a day to day or week to week basis, and muscle mass depends on factors in addition to plasma testosterone levels including exercise level. And step1mon, testosrone is produce only from Leydig cells in the testes.
___________________
Mr. Physiology. An answering machine.
|
| cyra
Moderator
Topics: 29
Posts: 844
|
Great question paganini...and excellent explaination..Thankyou!
How is testosterone cyprionate administered?
|
| paganini
Forum Senior
Topics: 26
Posts: 153
|
intramuscularly
___________________
Mr. Physiology. An answering machine.
|
| reet
Forum Fanatic
Topics: 152
Posts: 1,411
|
paganini- even i thought the answer B. THANKS FR EXCELLENT EXPLAINATION
___________________
Live as u were to die tommorow. Learn as if u were to live forever.
|
|
| |
| | | | | | | | |
