Quote:
Originally Posted by Seetal
also, real sorry sabio, but the theories you found are rather confusing. pls look at the adrenal hormone metabolism carefully. there is a beautiful easy to understand explanation for any of the diseases. this adrenal hormone pathways can be found online too. (pathways of adrenal steroid synthesis)
good luck sabio!!
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Hi Seetal,
Thank you very much for the nice explanation.
Our friend lemontea did not specify whether he's asking about Pituitary or Ectopic ACTH causes of Cushing (where we have elevated ACTH) OR Adrenal or Iatrogenic Cushing (where we have depressed ACTH). I was thinking that he must be confused because in both the situations you have hypokalemia (checked all references).
So what you said, explains how high ACTH causes the effects but you did not tell us how a low ACTH (Cushing Syndrome) will cause low potassium!
Also there's another mistake in your answer, you said that 11-deoxycorticosterone is in the cortisol (fasciculata) pathway while it's not. 11-deoxycorticosterone is present in the aldosterone (granulosa) pathway and it should NOT be stimulated by ACTH. In the fasciculata pathway we have 11-Deoxycortisol which has no mineralocorticoid activity whatsoever.
The cause of hypokalemia and alkalosis is not yet understood. Because in Cushing syndrome they consistently have found normal renin and normal aldosterone blood levels. Therefore, they are thinking that it must be the cortisol itself is the cause of hypokalemia.
Check the following references;
http://www.ncbi.nlm.nih.gov/pubmed/12381548 (read the last 4 lines where they said there's no relation between ACTH level and hypokalemia and ....etc)
Also this article
http://xnet.kp.org/permanentejournal...ertension.html
And several other articles on the web