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Discussion Starter · #1 ·
A 75 year old man undergoes surgical repair of femoral fracture. During surgery he receives half a liter of fluid more than he loses. This fluid excess is most likely to cause an acute decrease of which of the following hormones?

A- Angiotensin II
B- Atrial Natriuretic Peptide
C- Thyroxine
D- Testosterone
E- Parathyroid hormone
 

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Discussion Starter · #8 ·
Agreed - Angiotensin - but is Angiotensin II considered a hormone?
Of course it is a hormone. It is formed the conversion of Angiotensin I (which came from Angiotensinogen formed in the liver) in the lung and released into the circulation and acts on remote sites and is part of the renin-angiotensin system.
Hormone = is a chemical released by a cell in one part of the body, that sends out messages that affect cells in other parts of the organism.
 

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yeah definitely hormone

FYI, vitamin D is too considered a hormone due to its mechanisms of synthesis to its active state and its works in general (new studies)

no relevance here, it just popped in my mind.
 

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answer is B

Hi,

i am new to this forum, i am happy to see lots of motivations around, i am also preparing for step1 , due in three months. ok for this the answer suppose to be B ( Atrial Natriuretic peptide ) as its the only one that works immediately, not angiotensin II that works as chronic regulation.
The question said which one will cause acute decrease.

thanks,
 

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It's not ANP

Hi,

i am new to this forum, i am happy to see lots of motivations around, i am also preparing for step1 , due in three months. ok for this the answer suppose to be B ( Atrial Natriuretic peptide ) as its the only one that works immediately, not angiotensin II that works as chronic regulation.
The question said which one will cause acute decrease.

thanks,
ANP should not decrease but rather increase when there's fluid access. It encourages natriuresis to get rid of the excess fluid.

In addition, ATII true has long term effects but it's level will acutely responds to changes in fluid volume but the effects of it's response takes time. In other words, the ATII will acutely decrease after fluid access but that will not lead to aldosterone mediated less Na retention only after sometime.

The correct answer is A
 
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