Re: When dietary methionine and cysteine are low, what are the priorities?
- --- In Autism-Mercury@y..., Susan Owens <lwo@i...> wrote:
> Listmates,deficient in
> This study gives a look at what happens if there is a reason for
> metallothionein induction in someone who has become recently
> sulfur, and is probably already deficient in glutathione.live a
> Of course, this is looking at an 8 day trial in animals that only
> few years. The results might be quite different if the dietrestriction
> had been extended for months, or even through an entire lifetime.This study is completely irrelevant, off point, and misleading in the
context of the autism mercury list.
DIETARY INTAKE is only a surrogate for body composition. Some
people's bodies hold onto the "sulfur" avidly, others spill it fast.
The more appropriate question is WHAT IS SOMEONE'S PLASMA CYSTEINE OR
BLOOD GLUTATHIONE LEVEL. Mercury intoxication is well known to
decouple dietary intake from actual levels (we certainly spend enough
time talking about that and its implications on list) so the paper
below only has some hope of conveying useful information if diet is
ignored and instead body levels of available thiols are considered.
Interpreted as above, this paper suggests sulfation problems should be
nonexistent in "high sulfur" people, which is contrary to clinical
> 1: Toxicol Appl Pharmacol 1990 Feb;102(2):259-67
> Effect of sulfhydryl-deficient diets on hepatic metallothionein,
> and adenosine 3'-phosphate 5'-phosphosulfate (PAPS) levels in rats.of Kansas
> Sendelbach LE, White CA, Howell S, Gregus Z, Klaassen CD.
> Department of Pharmacology, Toxicology and Therapeutics, University
> Medical Center, Kansas City 66103.decrease
> Low dietary concentrations of methionine and cysteine are known to
> hepatic glutathione content. However, it is not known if restrictingthe
> dietarylevels of
> content of these sulfur containing amino acids also affects hepatic
> adenosine 3'-phosphate 5'-phosphosulfate (PAPS), the cofactor forsulfation, or
> metallothionein, a protein rich in sulfhydryl groups. Rats were feddiets
> lacking cysteine and containing various concentrations of methionine(0.15,
> or 0.6%) for 8 days. Control diet contained 0.3% each of methionine
> cysteine. Hepatic glutathione levels were decreased approximately75% in rats
> fed diets containing 0.15 or 0.3% methionine. In contrast, PAPS andhepatic
> metallothionein concentrations were not decreased by the lowsulfhydryl diets.
> Additionally, rats on the various diets were challenged by theto the same
> administration of
> ZnCl2 (3 mmol/kg. sc). In both control rats and rats maintained on
> sulfhydryl-deficient diets, ZnCl2 increased hepatic metallothionein
> level. However, significantly lower levels of PAPS were observedafter ZnCl2 in
> rats receiving sulfhydryl-deficient diets than in controls. Insummary,
> restriction of dietary sulfhydryl markedly decreases the hepaticcontent of
> glutathione and has a minor effect on PAPS concentration, but doesnot decrease
> the basal hepatic concentration of metallothionein or its inductionby ZnCl2.
> PMID: 2300970