Posted by Larry Hoover on November 7, 2004, at 11:07:11
In reply to Re: dopamine oxidation » Larry Hoover, posted by raybakes on November 7, 2004, at 5:06:24
>
> > The ascorbyl radical can then participate in chain reactions, but it is less reactive than the originating free radical. Glutathione quenches the ascorbyl radical, but is itself now a radical. There are a few processes by which glutathione is regenerated, and one of those is via alphalipoic acid.
> >
> >
> Hi Lar,
>
> I can only tell you what if feels like - I think high dose ascorbate would be fine with someone with normal health. I know if I take over 1 gramme of magensium ascorbate, I feel incredibly ill, mentally.Maybe that's the magnesium "talking"?
> I understand the outline that you give about how all the antioxidant systems working in concert produce radicals or become radicals in the process of dealing with a free radical, but matching how I feel to what you say, there must be something else going on.
I looked at the toxicity of vitamin C, and two possible mechanisms come to mind. One involves iron toxicity, exacerbated by the activation by ascorbate. Those with hemochromatosis are particularly vulnerable to this effect. The other mechanism involves enhanced excretion of uric acid. That might leave one vulnerable to peroxynitrite, as uric acid is an excellent peroxynitrite scavenger.
> I feel my antioxidant system is extremely fragile, and can probably only work at a certain rate - It probably has a few weak links in the chain - enzymes that when pushed too hard, run out of co-factors (NADPH to reduce glutathione is a suspect, particularly because it requires energy, something my brain lacks!).
You're the expert on how things make you feel, Ray. All I can do is offer you knew thoughts to try on for size.
> So ascorbate could produce more ascorbyl radicals than glutathione could mop up before I started running low on NADPH. With NADPH running low, hydrogen ions build up in the cell, the pH drops, all enzymes fail, and I end up with millions more free radicals that I started with!
I really doubt there's a pH mechanism at play. There are many many ways for cells to adjust pH. There are substantial buffer systems in place, just for that purpose. Do you understand the chemistry of buffer systems?
> Just a theory, but that's how it sort of feels!
>
> RayTry a different source of ascorbate, would be my suggestion.
Lar
poster:Larry Hoover
thread:404137
URL: http://www.dr-bob.org/babble/alter/20041022/msgs/412866.html