Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

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pamojja
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Re: Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

Post Number:#16  Post by pamojja » Wed Jul 11, 2018 4:14 am

OxC wrote:we would need to multiply by a factor of about 280 (heaven forbid pamojja gets wind of this outrageous nonsense! :) ..28 mg.


Well then, happy daily injections of DHAA. ;-)

I'll continue with oral mega-doses which already served me well with my conditions.

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Re: Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

Post Number:#17  Post by tjohnson_nb » Thu Jul 12, 2018 6:42 am

OxC wrote:Yes, there is a difference. Human RBCs take up DHAA 10 – 20 times faster than mouse RBCs. It’s all detailed in this article better than I could ever do: Low Red Blood Cell Vitamin C Concentrations Induce Red Blood Cell Fragility: A Link to Diabetes Via Glucose, Glucose Transporters, and Dehydroascorbic Acid. I assume rat RBCs are similar to mouse RBCs. The bottom line, in my view, is that humans might require DHAA doses 10 – 20 times higher than rats for the same effect. What might that mean in terms of how much DHAA that really is?

In the article I previously cited, where the images were acquired in rats, the actual dose of DHAA injected was about 5 micrograms. If we first calculated the dose for a human based on the weight difference versus a rat, we would need to multiply by a factor of about 280 (heaven forbid pamojja gets wind of this outrageous nonsense! :) ). Then if we increased that by a factor of 20 to compensate for the RBC absorption difference, we get 5 micrograms X 280 X 20 = 28,000 micrograms, or 28 mg.

You have the wrong link above, I believe this is the article you referred to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740302/
I would be concerned infusing a large amount of DHAA that it would deplete GSH in RBCs trying to deal with all that recycling
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Re: Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

Post Number:#18  Post by OxC » Thu Jul 12, 2018 7:54 am

tjohnson_nb wrote:You have the wrong link above, I believe this is the article you referred to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740302/
I would be concerned infusing a large amount of DHAA that it would deplete GSH in RBCs trying to deal with all that recycling

Thanks, I edited the original to correct the link. Regarding GSH, you might find this interesting: Stimulation of the pentose phosphate pathway and glutathione levels by dehydroascorbate, the oxidized form of vitamin C
Douglas Q. Kitt, founder of ReCverin LLC, sellers of stabilized dehydroascorbic acid solutions.

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Re: Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

Post Number:#19  Post by tjohnson_nb » Thu Jul 12, 2018 9:22 am

OxC wrote:Thanks, I edited the original to correct the link. Regarding GSH, you might find this interesting: Stimulation of the pentose phosphate pathway and glutathione levels by dehydroascorbate, the oxidized form of vitamin C

Does this apply to RBCs, it seems to be talking about lymphocytes.
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Re: Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

Post Number:#20  Post by OxC » Thu Jul 12, 2018 10:31 am

tjohnson_nb wrote:Does this apply to RBCs, it seems to be talking about lymphocytes.

Referring to this excellent narrative https://allaboutblood.com/2013/08/06/er ... etabolism/
The Hexose Monophosphate Shunt:
Erythrocytes are subjected to a high degree of oxidative stress from exposure to drugs and chemicals and from oxygen transport... Glutathione is a tripeptide that scavenges reactive oxygen species and is oxidized in the process. Glutathione reductase regenerates glutathione by using NADPH as an electron donor. The only non-mitochondrial source of NADPH is the hexose monophosphate shunt...Normally about 10% of the glucose is metabolized through this shunt. When the erythrocyte is faced by an oxidizing stress almost 90% of the glucose may be metabolized through the shunt

Whether or not the mechanism of stimulating the hexose monophosphate shunt (aka pentose phosphate pathway or PPP) is the same in RBCs as in lymphocytes, I don't know. Whether or not the net overall effect is increased concentration
of glutathione as it is in lymphocytes, I don't know. I do know that DHAA has been demonstrated to induce NADPH production through the PPP via a number of mechanisms in many, many cell types and so this appears to be a general effect. Reported mechanisms have included inhibiting hexokinase, stimulation of the PPP enzymes G6PD, 6-phosphogluconate dehydrogenase, and transaldolase, and other mechanisms.
Douglas Q. Kitt, founder of ReCverin LLC, sellers of stabilized dehydroascorbic acid solutions.

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Re: Vitamin C Function in the Brain: Vital Role of the Ascorbate Transporter (SVCT2)

Post Number:#21  Post by tjohnson_nb » Fri Jul 13, 2018 8:27 am

OxC wrote:The Hexose Monophosphate Shunt:
Erythrocytes are subjected to a high degree of oxidative stress from exposure to drugs and chemicals and from oxygen transport... Glutathione is a tripeptide that scavenges reactive oxygen species and is oxidized in the process. Glutathione reductase regenerates glutathione by using NADPH as an electron donor. The only non-mitochondrial source of NADPH is the hexose monophosphate shunt...Normally about 10% of the glucose is metabolized through this shunt. When the erythrocyte is faced by an oxidizing stress almost 90% of the glucose may be metabolized through the shunt

Whether or not the mechanism of stimulating the hexose monophosphate shunt (aka pentose phosphate pathway or PPP) is the same in RBCs as in lymphocytes, I don't know. Whether or not the net overall effect is increased concentration
of glutathione as it is in lymphocytes, I don't know. I do know that DHAA has been demonstrated to induce NADPH production through the PPP via a number of mechanisms in many, many cell types and so this appears to be a general effect. Reported mechanisms have included inhibiting hexokinase, stimulation of the PPP enzymes G6PD, 6-phosphogluconate dehydrogenase, and transaldolase, and other mechanisms.

Very interesting - will study this. :)
'Always' and 'never' are 2 words you should always remember never to use.


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