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  #1  
Old 09-08-2013
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Biochemistry ALA synthase increase in Alcohol

ALA synthase increase in Alcohol but decrease in excess of glucose...plz explain
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Old 09-08-2013
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alcohol induces P450 (P450 needs heme for synthesis)------>decreases heme------>decreased heme-increases enzyme activity
unfortunately i dont know whats the mechanism beyond Glc induced suppression of enzyme
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Old 09-09-2013
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Thanxz examiner..any1 plz also explaon relation between glucose and ALA synthase.
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Old 09-09-2013
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Thumbs Up ALA synthase vs alcohol

Where did u find that glucose vs ALA synthase ???i searched whole biochem metabolism..no where i found the link...if u find the anser..plz post it..and that alochol induces p450 in chronic condition..not acute alcohol(inhibits p450)
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Old 09-09-2013
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Default ALA synthase vs alcohol

Hey come on ...you got that from wikipedia i think..if so thats controversial( check for the citation they gave)..so no need to worry...nothing controversial comes on boards..so take it easy.all the best.
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Old 09-09-2013
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nops not wikipedia...Its in Uworld...Q.Id 1339 ...
In explanation it is written that glucose and intravenous heme preparations decrese ALA synthase activity so decrease acute intermittent porphria symptoms.
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Old 09-09-2013
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Well I'm going to logically think this one through increase in excess glucose shunts glucose Towards fatty acid synthesis. So no going through TCA. hence decrease in succinyl CoA and therefore decrease in ala synthase. Once again this is my reasoning and anyone please feel to correct me
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Old 09-09-2013
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Default glucose vs alasynthase

ThankGod!!!!!i got the anser...its simple...Excess heme represses ALA synthase. this is direct.
Go to page no.188 in biochem,kaplan...or citricacid cycle diagram......there it shows succinyl-CoA used in heme synthesis....so lots of glucose gives lots of succinyl-CoA and so lots of heme which decreases ALAsynthase activity.
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Old 09-09-2013
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Hi Haseebkat...u told excess glucose shunted to FA synthesis...it does indeed...but before that..excess glucose must and should enter citricacid cycle in everycell with mitochondrion...this ration is high(citricacid to FAsynthesis) FA synthesis doesnt occur in everycell ...so citricacid cycle effects ALA synthase through increase in SuccinylCo-A.
And if succinylCo-A decreases then there would be decrease in heme synthesis...and this will increase ALA-synthase activity( coz excess heme represses ALAsynthase)..
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Old 09-10-2013
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Yes dr Joe sorry it's very late here 3 a.m and thank you for the explanation
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Default okay

okay..goodnyt
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Old 09-10-2013
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Default oops!!!

ALAS-1 transcription is upregulated by peroxisome proliferator-activated receptor coactivator 1 (PGC-1). Transcription of PGC-1 is regulated by glucose levels. Hypoglycemia induces PGC-1 production, increasing ALAS-1 and heme synthesis. This promotes the clinical appearance of the acute porphyrias."
this is the actual explanation...the one which i gave works only in normal heme synthesis but in AIP, increase in succinylcoA will give more substrate for Prophobilingen deaminase which is deficient...and ultimately no heme to repress ALAsynthase.Im sorry i didnt think of AIP at all while looking for link between glucose and ALAsynthase.
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