Tuesday, May 28, 2019

Metform (11) metformin vs mtG3Pdh knockout

This paper is interesting (and badly written):

A high carbohydrate diet does not induce hyperglycaemia in a mitochondrial glycerol-3-phosphate dehydrogenase-deficient mouse

It uses a mtG3Pdh knockout mouse, which is essentially a mouse which behaves as if it was on an enormous dose of metformin without all of that toxic blockade of complex I which gives a potentially lethal lactic acidosis at high dose rates. If you feed these mice standard crapinabag they are phenotypically normal. If you feed them a diet consisting some casein, a little PUFA to avoid EFA deficiency and the rest of the calories from pure sucrose they become rather interesting.

Eating pure sucrose does not make normal mice fat. It does make them insulin resistant and hyperinsulinaemic and, of course, insulin resistant adipocytes refuse to retain fat unless insulin action is facilitated by the oxidation of PUFA. Hence the normal body weight.

But the knockout mice actually become slim on sucrose. Here are the data, we can ignore the heterozygous (HET) groups:

They are slim because insulin levels are low. From the Protons perspective the function of the glycerophosphate shuttle in the pancreas is to drive enough reverse electron transport through complex I to trigger insulin release. Less RET, less insulin release, less fat storage, less hunger. Here is the isolated response of the perfused pancreas model to hyperglycaemia:

First phase insulin release is about a third of that in the normal mice. The mice are not diabetic because, in the absence of the glycerophosphate shuttle, RET to allow insulin signalling is generated by beta oxidation supplying electron transfering flavoprotein the CoQ couple via mtETFdh. Insulin signalling still happens but at the "cost" of increased lipid oxidation in the peripheral tissues.

What doesn't happen is sucrose induced insulin resistance. Again I consider this is triggered via the glycerophosphate shuttle causing RET at a level to shut down insulin signalling, which simply doesn't happen in the knockout mice. Lack of glycerophosphate shuttle also stops the generation of insulin-induced insulin resistance under conditions of high insulin concentrations coupled with energy replete cells.

Does anyone recall this figure from Metformin (01) post back in 2017?

Insulin was given at 90 minutes. At 150 minutes in the upper (non metformin-ed) rats insulin action starts to fail, at about the correct time for insulin-induced insulin resistance. By 180 minutes that upper trace, the non-metformin group, shows an upward trend in glucose as exogenous insulin levels are no longer high enough to overcome insulin-induced insulin resistance (the rats are DM T1 under insulin withdrawal).

At 180 minutes in the lower line showing metformin treated rats we can see the continued action of insulin being facilitated by the metformin because it blocks insulin-induced insulin resistance. It was mention in the comments to the post that, clinically, this effect of metformin might worsen the possibility of hypos in humans if combined with exogenous insulin usage. Potentially fatal hypos.

So what happens if you inject a sucrose treated mtG3Pdh knockout mouse with exogenous insulin to check their insulin sensitivity? Insulin sensitivity is preserved, to fatal effect:

All of the mice with the mtG3Pdh knockout died under exogenous insulin. This is exactly how I would expect metformin to behave in humans using insulin. A functional glycerophosphate shuttle allowed a sucrose diet to block this fatal sensitivity to exogenous insulin.

Obviously the mtG3Pdh mice have a normal complex I. Might they still develop lactic acidosis? Sadly the group didn't look at this (they had no idea back in 2003 that they had developed a meformin mimic model mouse). I do think there might be some elevation of systemic lactate despite a normal complex I.

In the absence of the glycerophosphate shuttle glycolysis is going to run directly to lactate to maintain redox balance. If glycolysis proceeds at a rate in excess of oxidation of the lactate within mitochondria (recall oxphos is slow compared to glycolysis) then some glycolytic lactate will spill outwards, though this is never likely to reach ICU-needing levels. No need to have a complex I blockade to generate mild lactic acidosis.

Does this metformin-ed like mouse have the exercise gains seen in human cyclists after popping 500mg of metformin pre-race?

That requires that we look at a different model.



Balam said...

I'm a guy who takes metformin because my blood sugar drops really bad after I eat a meal (a few hours after) and it's hard to get through the day without sugar snacking because of this. I avoid processed sugars so it's not that I'm eating cakes and snickers. In an effort to lose weight I have to eat less and so I have to deal with the crashes somehow.

I thought that taking metformin would reduce insulin levels in the blood so glucose wouldn't drop so badly. I guess the increased effectiveness of insulin after metformin means the insulin sucks up more glucose? Do the metformin test results you present mean that my crash will actually be worse and I should avoid it?

Peter said...

Hi Balam, overall metformin is one of the more effective weight loss drugs around. If you are having what are described as hypoglycaemic episodes it might be a useful ploy to avoid both the precipitating hyperglycaemia and hyperinsulinaemia in the first place. No one has a "hypo" after a ribeye steak. Unless they eat the fries that are on the same plate, which would be a mistake.....


ctviggen said...

Balam, I wonder if you have a glucagon issue. This is a simplistic way of comparing glucagon and insulin:


Basically, blood sugar goes up, insulin goes up to counteract. At some point, blood sugar goes down to a certain point, and glucagon should go up to raise blood sugar. Maybe you have an error in glucagon production? About the only to fix this are to see if you can correct the pancreas and liver, which is low carb/keto and if you can do it intermittent and long term fasting. Other than this, I don't know of anything else.

Balam said...

ctvigen: I do have a recently uncovered issue where I don't produce Luteinising Hormone (LH), and they used HCG to determine it was not my testicles but probably a pituitary issue (HCG stimulated the testes perfectly, so it had to be an upstream problem). I got the whole blood testing done in the first place just trying to figure out why my blood sugar crashed so bad - I even had a diabetes 1 roommate who noted that my fatigue symptoms in a crash were very similar to his when he doesn't manage his insulin well.

Looking up any connection between hypothyroidism and glucagon (a new word to me, thank you!) it does look like there is a glucagon issue.
"The role of gluconeogenesis is reduced in hypothyroidism, both in skeletal muscle and in adipose tissue.[23] Glycogenolysis is also impaired in hypothyroidism.[24] These biochemical defects lead to a delayed recovery from hypoglycemia."

I agree with both you and Peter that I'm going to have to go Keto. I'm currently intermittent fasting because I noted if I don't eat I don't have to suffer the drop, so I can function normally for at least half the day. If ketones can shortcircuit the whole process it may have to be a lifetime choice for me, esp if it's true that my glucagon process is messed up.

Passthecream said...

Hi Peter, deeply interesting to me because I am a recovering metformin addict. I seem to managing without it now. Balam, that is also v. interesting. I have a young relative who is hyperthyroid, and appetite swings are a big issue with him.

Someone linked Grant Genereux's vitamin A writings here recently and I finally went and had a look at his blog and read his 'poisoning for profit ebook'. I thought it would be a ho-hum experience from yet another internet quack but not so, it is deeply interesting if for no other reason than to show how and why feeding rodents a diet of casein and lard will do them great harm in a very short amount of time. Many rats have suffered needlessly and pointlessly in the name of dietary research. As we know.

But also, this set of TLDR:

1 The theory of retinol and friends as an essential 'vitamin' is convincingly shown to be a load of old bollocks. Quite the opposite seems true.
2 Brightly coloured vegetables and fish oil - eat them at your peril!!!
3 Putting cream on your skin which contains retinyl palmitate and heading down the beach is like giving yourself a gentle burst of flaming napalm.
4 Might have to change my alias, drop the cream reference. Dang.
5 Eating well just got a bit more complicated but also simpler.


Gyan said...

Genereux's writings are not as logical as he thinks. He believes that "he has presented ample evidence against against the sub-theory that vitamin-A is needed for stem cell differentiation."
Pg 65 of the Poisonin book.

Frankly, I failed to see any evidence whatsoever. If the symptoms of vitamin-A deficiency as the same as that of vitamin-A toxicity, does that mean that there exists no requirement of vitamin-A at all?

And why do carnivores are said to preferentially eat liver of their victims? Haven't people been eating liver and butter for ages.

Passthecream said...

Difficult questions. I'm no expert. Some of his writing is definitely a bit 'shouty' and at times he is just as guilty of the unfounded assertions that he accuses others of. Some wild extrapolations there too. Otoh I still found some bits quite convincing. Easy to check up on too.

Vitamin A hypervitaminosis definitely exists in humans and can be lethal so maybe we don't have a capacity for sustained high levels of A intake? Is this therefore a disease of civilisation, excess. Eg if you take the RDA as valid then a large red capsicum will take you to around 100% of it. Mix that with a few slices of cheese, bread'n butter, a boiled egg with lettuce and a glass of milk to wash it down, that will put you into serious excess. Then later on you can take another meal with more rich foods like that. And if you are taking a daily fish oil pill for your pains ...

Gyan said...

Genereux regards vitamin-A as toxic in itself. Not just in excess--that would be the standard view Genereux is dissenting from.
So, is vitamin-A in its various forms merely a widespread plant toxin that animals have to accommodate to somehow? Without there being a positive role of vitamin-A in animal metabolism?
Is all vitamin-A biochemistry just detoxification?

Why is Vitamin-A found in mammalian milk?
His numbers are very dubious. IS it really so that modern American intake of vitamin-A is 100-1000 times that in historical times?. That the incidence of auto-immune disorders in the West upto 1000 times that in poor countries?

And his discussion of role of Vitamin-A in vision is simply shoddy. He says vision can't be a chemical reaction as the relevant reaction is exothermic and takes place (some large number) times a day. Thus eyes would melt !!! --without working out the total energy liberated and the estimated temperature increase.

Thus, he says vision must be an electric process. He fails to realize that in body, chemical and electric are not mutually exclusive.

This subject, though very interesting and it is all too likely that modern medicine has made some howlers here, needs a more sober writer. Is it likely that his hair went from grey to 90% black post-his vitamin-A depleted diet and as he took some lutein supplement went to 70% grey?
And went to 90% black again as he discontinued lutein?

Passthecream said...

'This subject, though very interesting and it is all too likely that modern medicine has made some howlers here, needs a more sober writer. '

I agree
- and there are some howlers in there alright but there is good stuff too.
It needs some reputable basic research.

It has set me looking and thinking however.
Many of the high A foods are foods with which I have had strange problems, not necessarily attributable to vit A but I am testing the hypothesis with an N=1 trial. It isn't the least bit onerous appart from the cheese.

Gyan said...

Is vitamin-D a well-known toxin as Genereux says at pg 322?

Passthecream said...

Not to my knowledge. The opposite is true!

Stepping away from that particular strange collection of ideas for a moment:

The storage limits and the potential dangers of vit A are widely publicised and accepted so that's nothing new. I am interested to know what really are the base experiments which established and maintain the recommendations and which are used to justify fortification. Is it as he says? Does it all point back to those original experiments from approx 100 years ago? It sounds strongly reminiscent of the whole cholesterol fiasco, a similar type of a collection of heavily defended and often repeated theories based in bad science and which don't stand close examination. The dynamics of that seem to be the same. It is a stubbornly held and pernicious set of medical beliefs.

It is almost impossible to find advice on the interwebz about how to lower your vitamin A levels and which vit A containing foods are best avoided. It was tedious to compile a list of the vit A levels vs foods I like to eat.

Gyan said...

As an Indian it was curious to have India lauded as a healthy nation relative to USA. Though he is probably correct that we have lower rates of auto-immune disorders than the West.
I have too always wondered about these RDAs. Curiously the scientific advances of last half century have bypassed the old established RDAs. I would have thought there would be steady research in refining these values but there seems to be no current work in this field

Gyan said...

He is also awfully coy on whether vit-A has any legitimate bodily function.
And I don't buy that liver stores vit-A as detoxification
Why won't body try to expel a toxin instead of sequestering it in liver?

Richard B said...

Peter - I have been enjoying your site for a long time but I cannot work out whether you think metformin is a good idea in certain circumstances. As an LCHF eater I find my glucose levels are hovering around 100 most of the day, sometimes up to 115, occasionally dropping into the 80s. A1C is between 5.2 and 5.5...not bad but not ideal. It was 5.8 at one point. I am not sure whether metformin is a good idea just to nudge those numbers down somewhat.

Another long running question I have is why you are worried about excess protein and the TCA cycle. I bought and read Nick Lane's books (great stuff), including the chapter you point to as your argument, but I still cannot quite see the connection. Protein metabolism creates oxidative stress? I eat moderate protein anyway, but this remains one of the biggest debate points in the LCHF world (+keto + carnivore and all other spawn of LC)...your opinion matters to me on this.

Passthecream said...

Dang I lost a long and obviously brilliant comment. Everyone can relax again.

Gyan, please have a look through his first version 'Extinguishing the fires of hell' It seems more reasonable to me. The Finnish example is intriguing as is the North East Canadian data post the mid '90s. It's a free ebook, so I guess take it or leave it. He's not selling anything afaict. I seek out the useful parts and see where they lead. Genereux freely admits the flimsy nature of some of his speculations and invites feedback.

I was also going to mention that is terrifically easy to overdose on vit A if you follow a HFLC way of eating. Regularly eating cheese, cream, butter, liver, eggs, berries, leafy greens and herbs perhaps, chilli, red pepper and tomatoes - you're way! One portion of sweet potato and you're in deep trouble.

There is an over-abundance of it in the food chain. Don't mention fruit. And Americans put it in flour and milk, just in case you miss out. Something rotten there...

Do they really put vitamin A in the sugar in Mexico???????

Passthecream said...

.. way over! ...

le frota said...


I was wondering if that's one of the reasons people are being successful eating only steaks? The Andersen family comes to mind, they've been eating only steaks for 20 years and dont seem to have aged a bit lol.

I'm still not convinced of all of this, but I'm trying to avoid it since my problem is always that I get too much of that by eating liver and eggs, so even for the normal standards I worry I consume too much.

Balam said...

Keto has been working out great for me - I haven't had a single really low drop in blood sugar (based on my mood and ability to work) ever since the 'keto flu' period (If only I knew ahead of time to megadose sodium, magnesium and potassium to get through the keto flu part painlessly). I'm also taking the metformin since you said it will also help with the weight loss. In addition the more stable blood sugar is making fasting a breeze, whereas it was taking up enormous willpower and shame before. Thank you all for the recommendation, my life has become much easier since.

There was a lot of fear going into the diet, especially since there are hundreds of articles saying that keto is going to kill me via cancer or whatever, until I read about 'Angus Barbieri' the man who fasted for 382 days. Apparently the body uses ketosis/ketones for energy during long fasts so if this guy could live for a year purely on ketones then keto can't be a fatal diet.

Passthecream said...

Le Frota: Lamb chops are good too. Free range poultry. Etc. Cauliflower, onions, most spices are ok. Peeled simple vegetables if you feel the need but not solanums, sweet potatoes or carrots. Skip the dairy foods.

I have been minimising A as much as possible for a week now and it is as good a change as when I first gave up wheat and sugar. I had certainly been having too much of it.

Gyan7 Jun 2019, 08:12:00: "
Genereux regards vitamin-A as toxic in itself. Not just in excess--that would be the standard view Genereux is dissenting from."

He certainly needs the services of a good editor but I don't think that is quite right. To briefly summarise what I think he is saying is that:

1) it is multifunction but the main role is innate immunity (eg like salt and etc.) So there is a need for some of it. It's a tightly controlled bug killer. So, the RDA is way too high for people who live in a hygienic and relatively disease free environment. It is particularly toxic in the form of free retinoic acid

2) it accumulates if not used and storage capacity is finite. Liver is the usual location and liver volume is small in the very young, increases to about age 18 then reduces by almost half by age 65.

3) the toxicities exhibit a cluster of symptoms which are very similar to a range of what are currently thought to be autoimmune diseases, also similar the range of known symptoms of a transient vit A overdose.

Gyan said...

He should avoid saying that vitamin-A is not a vitamin at all but a toxic molecule. This is endless.
The matter of liver storage, daily depletion and intake is quantitative and can not be hand waved by pointing to finiteness of the storage. How much is liver actually capable of storing?

I would suppose that avoidance of liver and fish oils should take care of going over with vit-A intake. Beta-carotenes in fruits and vegetables are probably poorly absorbed unless vegetables are eaten fried.

Gyan said...

In the breast cancer book, he brings up the objection that vit-A is found in the breast milk so it must be essential. He answers by the example of DDT that occurs in trace amounts in the breast milk. So, vit-A in the breast milk is a toxin that mother accidentally passes on to the child!.

So your argument that he is saying that vit-A "is multifunction but the main role is innate immunity" does not hold. He is specific that vit-A is toxic and has no function in the human body.
Indeed, in his 3 books, I doubt if he has mentioned existence of vit-A receptors. He says flat-out that vit-A disturbs DNA causing 300 types of mutations.

His biochemistry, if it can be called so, is essentially different from what we are used to.

Gyan said...

By the way Genereux is wrong about allied POWs subsisting on zero A diet. I easily found on net many papers on this topic. The Japanese were giving them vegetables -- 100 g /d was the ration. They were also getting Red Cross parcels.

le frota said...


I dont buy either that vit A is a toxin, I believe it has its use, but maybe there's more to the overconsumption of it and not balancing with enough K and D. I was thinking about how it's easy to get A, but most people dont get sufficient or are deficient on K and D.

So you can either reduce your A or balance the others. Just a thought here.

Passthecream said...

Anything can be a toxin if it is in the wrong place, the wrong amount, unguarded or as you say out of balance. Put most of that hypothesising to one side and just go check up the numbers, the epidemiology. References are given. Devise a plausible explanation for those population patterns.

Try cutting out those foods for a few days. It's a fun thing to do, cleaning out the fridge, revising your menu - unless you are so addicted to those things that you can't handle it. Going cold turkey on A is giving interesting results for me very quickly much as he suggested it would.

I do not think that deep cold saltwater fish and fish oil is the natural food of humans. The milk of domesticated animals might be a bit tricky too, coupled with a constant supply of out-of-season inbred fruits and vegetables. Eggs would not have been available all year long in the distant past. It is all too much.

Gyan, I think you are cherry picking his cherry picking.

Passthecream said...

Not my favourite person but an interesting interview in light of the above.


Bread nor milk in Australia are not usually supplemented with vit A but bread has mandatory folate.

Gyan said...

People have subsisted quite healthily on meat diet before--eg fatty meat diet prescribed by Dr Donaldson of Strong Medicine book. I guess fatty meat contains enough vit-A. It is strange that Genereux in writing hundreds and thousands of pages never comes down to telling us precisely what cuts of beef and bison is he using.

Passthecream said...

This is more Hyperlipid friendly:

"Retinol as electron carrier in redox signaling, "


'How can chronic vitamin A excess lead to pathology? The action of two inhibitory retinoids, AR (55) and fenretinide (105) may be informative. In cell culture experiments, these retinoids caused mitochondrial stress and necrotic cell death (25,58,106-109). Both retinoids are known to bind the PKCδ activation domain with similar affinity as retinol (28), but inexplicably they caused the hyper-activation of mitochondrial PKCδ (25) leading to cell death. This was reflected in one study by high levels of ROS (58), while in another AR-treated cells became depleted of ATP to a degree that they could no longer survive (107). The paradox, why AR (or feneretinide) can substitute for retinol as activating cofactors of PKCδ, but why this mode of activation leads to cell necrosis, remains unresolved. It is noteworthy that supranormal retinol levels (above 2 micromoles) are also toxic, as the inverted U-shaped retinol dose responses indicate (25). '

This includes the working definition of vit. A content:


'How Much Vitamin A Do We Need?

The recommendation for vitamin A intake is expressed as micrograms (mcg) of retinol activity equivalents (RAE). Retinol activity equivalents account for the fact that the body converts only a portion of beta-carotene to retinol. One RAE equals 1 mcg of retinol or 12 mcg of beta-carotene (Table 1). The Recommended Dietary Allowance (RDA) for vitamin A is 900 mcg/ day for adult males and 700 mcg/day for adult females.

Compared to vitamin A containing foods, it takes twice the amount of carotene rich foods to meet the body’s vitamin A requirements, so one may need to increase consumption of carotene containing plant foods to meet the RDA for vitamin A.

Studies indicate that vitamin A requirements may be increased due to hyperthyroidism, fever, infection, cold, and exposure to excessive amounts of sunlight. Those who consume excess alcohol or have renal disease should also increase intake of vitamin A.'

And presumably the inverse applies, those who don't have infection or consume excess alcohol should not increase their intake.

Passthecream said...

It would be amusing if the alleged benefits of alcohol assumption were owing to it counteracting the effects of a vitamin!!!

Gyan, food databases don't show much A in most land animal muscle meats. Liver and kidney numbers though, perhaps other organs are astronomical. Polar bears seem to hold the record and have larger livers just to be able to cope with, to store, the huge vit A levels in their favourite food, whole seal.

Some idiot ate a polar bear liver apparently. Their skin sloughed off not long afterwards. Genereux mentions avoiding lard from corn fed pigs.

Steak it is, and chops.

Passthecream said...

... consumption. Btw not the liver size but: 'healthy human liver contains 575 international units (IU) of vitamin A per gram while a polar bear's liver contains between 24,000 and 35,000 IU per gram'

Fred Lander said...

Ivor Cummins posted a link to a video presentation by Dr. Shulman yesterday and usually Ivor tries to not get super technical so as to reach a larger audience, so this is an exception. ( https://www.youtube.com/watch?v=TnvmEUUtoZw )

I took some notes and at minute 43:20 Dr. Shulman talks about metformin for 20 seconds and references Madiraju , Nature 2014. He says the metformin inhibits hepatic gluconeogenesis by decreasing the conversion of lactate to pyruvate and glycerol to dihydroxyacetone phosphate.

At 51:20 he discusses one approach to make use of the role of DAG and Acetyl COA in reversing type II diabetes and that is to promote mitochondrial fat oxidation through liver targeted mitochondrial uncoupling, with several studies as evidence. He said they have shown we can increase hepatic fat oxidation , which improves hepatic insulin sensitivity , and reduces hepatic gluconeogenesis through acetyl COA reduction, and this is heart healthy as it lowers VLDL and triglycerides and lowers muscle fat content and increases muscle insulin sensitivity. Targeting uncoupling will also lower liver fat and inflammation in 3 rodent models of NASH.

Somewhere he did show a chart with etomoxir and atglistatin to inhibit liver gluconeogenesis.

I got into ketosis by accident when I was experimenting with coconut oil to cook. My appetite plummeted and soon I lost 35 lbs. in 5 months. Next I know my A1c down to 5.0 and had been 5.8 several years before. No looking back for me, now over 3 years keto and having some concerns about arachidonic acid and mTOR and IGF-1 for cancer long term. Also elevated PSA three times and brought down with supplements, but still concerned as last time lymphocyte/monocyte ratio plummeted to 1.73 and had always been above 3. But that is another story.


Peter said...

Fred, Madiraju has been core to tying the Protons series of posts to the Metformin series. That 2014 paper is really good. I too have been giving some thought to IGF-1 in particular. The mouse models using rapamycin are interesting but not encouraging!


Fred Lander said...

Peter I downloaded the Madiraju paper and printed it out and am working my way through it.
For relaxation I found a interview of James DiNicolantonio by David Perlmutter last March, and since I am always looking for practical, cheap, ideas to help our health, James is one of my favorites. Just a two minute view would be appreciated as at minute 27:38 James mentions 4HNE and then linoleic acid metabolites and says these omega 6s are worse for our health, than sugar, by far.Then David goes on for a few seconds about some arachidonic acid metabolites impact on two endocannabinoid receptors to increase inflammation. They stop this line of talk at minute 29:30.

Any insights or comments would be appreciated, by you or any of this team you have helped assemble.