Talk:Gluconeogenesis

message: I'm no specialist, so have not edited.  Cannot gluconeogenesis also be caused by excess and/or too rapid protein intake?
MIchael 07:56, 24 July 2006 (UTC)
replies: text: The problem also exists for the section titled Pathway. It begins with pyruvate, but doesn't outline how substances such as lactic acid are converted to pyruvate to begin with. perhaps the problem is that different substances (amino acids, fatty acids, glycerol, etc.) are metabolized differently? Lactic acid, for example, is converted to pyruvate by the Cori cycle. Perhaps if only a few pathways exist to convert different classes of substances to pyruvate, these could all be described seratley, or a wikilink could be provided to an article describing each pathway? Theonly pathway currently mentioned in the article is the Cori cycle, which metabolizes lactic acid.
AhsenM (talk) 01:19, 8 September 2009 (UTC)
thread_title:  Disputed Image 

message: The accuracy of this article is disputed as the diagram shows glycolysis and not gluconeogenesis. The reverse reactions of glycolysis (shown in the image) can cause "new" glucose to be formed from small metabolites but there is more to gluconeogensis than just a reverse of glycolysis. Glycerol, from lipids, and deaminated amino acids are the major raw materials for forming new glucose.—Preceding unsigned comment added by Dbrouse (talk • contribs) Moved from article --Wafulz 05:38, 22 October 2006 (UTC)
replies: text: The problem also exists for the section titled Pathway. It begins with pyruvate, but doesn't outline how substances such as lactic acid are converted to pyruvate to begin with. perhaps the problem is that different substances (amino acids, fatty acids, glycerol, etc.) are metabolized differently? Lactic acid, for example, is converted to pyruvate by the Cori cycle. Perhaps if only a few pathways exist to convert different classes of substances to pyruvate, these could all be described seratley, or a wikilink could be provided to an article describing each pathway? Theonly pathway currently mentioned in the article is the Cori cycle, which metabolizes lactic acid.
AhsenM (talk) 01:19, 8 September 2009 (UTC)
thread_title: Dispute

message: In the statement concerning the existence of a futile cycle, the article implies that glycolysis and gluconeogenesis are independent processes.  This is an unfortunate conceptual error in understanding of the regulatory mechanisms of the two pathways.  Both processes DO occur at the same time; thus, a futile cycle is continually in effect to a certain degree.  The key is that one pathway is upregulated while the other is inhibited depending upon the given physiological state (ie. the presence of glucagon, insulin, epinephrine, etc).  The cellular benefit gained from allowing the seemingly wasteful futile cycle is that it allows a very rapid response by hepatocytes (kidney cortex, too) to systemic change in serum glucose levels...a very good thing indeed if one is being chased by an angry lion!  
If there are no disputes, I will come back and make the corrections with appropriate citation.
Awbacon 05:12, 8 September 2007 (UTC)
replies: text: In my reading of it, it doesn't seem to imply separate cycles. A futile cycle, however, would be when both pathways are operating at their full ability (thus negating each other physiologically). While both are continuously running, the inhibition of each cycle on the other through the three regulatory enzymes prevents it from becoming actually "futile". Schu1321 (talk) 07:41, 12 May 2008 (UTC)
replies: text: You mention some very relevant information. Perhaps add a section on the usefullness of gluconeogenesis, and another on the physiological states that inhibit or promote it? The clarification about the futile cycle would probably bes tfit into the section on usefullness. AhsenM (talk) 01:17, 8 September 2009 (UTC)
thread_title:  No futile cycle? 

message: This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 16:27, 10 November 2007 (UTC)
thread_title:  WikiProject class rating

message: I added a new image I made for the article and also reworked a large amount of the article text. I have the original image and can make changes easily, so if you notice any errors feel free to let me know and I can upload a revision. Schu1321 (talk) 07:43, 12 May 2008 (UTC)
thread_title:  New image, editing 

message: Hey, just remembering that we need an overview in this page of the process (how many substances created and destroyed, etc). Khullah (talk) 03:21, 1 December 2008 (UTC)
thread_title:  Overview 

message: In organisms in which glycerol is derived from glucose (e.g., humans and other mammals), glycerol is sometimes not considered a true gluconeogenic substrate, as it cannot be used to generate new glucose. I am not sure I understand. What do you think the butter I eat becomes after removing the fatty acids? --88.75.225.144 (talk) 19:14, 16 July 2010 (UTC)
thread_title:  Um? 

message: I have been trying to settle the question of whether free fatty acids (FFA) can be used in gluconeogenesis. Our article suggests, in accordance with many of the textbooks that, "Fatty acids cannot be converted into glucose in animals with the exception of odd-chain fatty acids". Biochemistry by Metzler and Metzler, among other sources, confirms this. The text describes the beta oxidation of FFA (with an even number of carbons) to acetyl-CoA (and acetoacetyl-CoA). Acetyl-CoA can, of course, enter the TCA and generate energy, but when there is excess acetyl-CoA, it begins to generate ketone bodies. This text avers that the animal body has an "inability to form the glucose precursors, pyruvate or oxaloacetate, from acetyl units..." which can lead to ketosis (the formation of ketone bodies from the excess acetyl). This seems to be the basis for the ubiquitous claim that FFA cannot be converted to glucose. However, a bit later on in the text, it is noted that acetone (one of the ketone body species formed from the oxidation of FFA) can be converted through a series of steps to pyruvate. In addition, another pathway is present for the conversion of acetone to pyruvate via 1,2-propanediol. The book than says, "As much as two thirds of this [acetone] may be converted to glucose". Hmm? Is this a splitting of hairs issue? It seems to me that while a FFA with an even number of carbons cannot directly be used in gluconeogenesis, it can be oxidized to acetyl-CoA which can be converted to ketone bodies, which can be used in gluconeogenesis. I found a paper that confirms this. (see edits) In addition, it looks like this question is a longstanding one in biochemistry, so I have amended the article to reflect some of the research.Michaplot (talk) 14:07, 11 September 2010 (UTC)
thread_title: Fatty Acid Issue

message: There seem to be a bit of confusion about whether "fats" in general can be converted into glucose by this process. My college and I had a discussion that we have been taught that only protein takes part in gluconeogenesis...but the following book Guyton & Hall, Textbook of Medical Physiology|year, 2000, 10th Edition| pages=780, has the following headline in bold
Formation of carbohydrates from proteins and 'fats - gluconeogenesis
In terms of fat, it is later referred to the glycerol portion excluding the fatty acid - now can someone help me define the fat in this context? Is it the fat found in vegi oil and french fries - those are cholesterol => steroids? Also is fatty acid part of fat? Please help me clarify this aspect. Flowright138 (talk) 07:47, 18 September 2011 (UTC)
thread_title:  Formation of carbohydrate from fats - from gluconeogenesis? 

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thread_title:  External links modified 

message: The current image: https://upload.wikimedia.org/wikipedia/commons/6/6b/Gluconeogenesis.png shows glycolysis as part of gluconeogenesis, which is incorrect.
As mentioned in the above discussion for Disputed Image (on the prior image), gluconeogenesis is the reverse pathway of glycolysis, although there are differences in participating enzymes.
I personally quite like the libretext image comparing the two: https://chem.libretexts.org/@api/deki/files/126125/Glycolysis_overview.svg?revision=1&size=bestfit&width=543&height=851
I'm not quite sure on the licensing yet for this image and will follow up later. Leaving a note for now.  — Preceding unsigned comment added by 2601:246:CD80:7790:C52:AB7C:19E2:A841 (talk) 14:55, 29 March 2021 (UTC)
thread_title:  Disputed Frontline Image