Dietary creatine utilization at all possible?

[Proctologi]

All,

Some of you may be aware of creatine being a relative newcomer
to the sports supplement field, and it seems to have garnered
some credibility, among diehard weight lifters, at least, sort
of like carb loading for marathoners.

But here's the problem: I was looking at the Merck, and it
states that in acid solution, conversion to creatinine is
complete. And creatine ---> creatinine (cyclization) is
irreversible. Even in neutral/alkaline solutions,
creatine/creatinine equilibbriums are achieved, altho no K is
specified.

Creatine (open chain) is transported into the muscle, for
phosphorylation. But, cyclized, it can only be excreted, and,
being irreversible, cannot be re-opened for possible use.

So how, then, is dietary creatine shown to be effective, and
according to some citing studies, proven to increase muscle
creatine/creatine phospate?

It seems that the Merck is not prone to hyperbole, so I am
assuming the cite of complete conversion to be true--and am
also assuming it to be fairly rapid, esp. in a pH 2
environment, like the stomach.

Note that creatine is synthesized in the kidney for transport
to muscle tissue. Creatinine is excreted by the kidney, and is
a normal component of urine.

TIA for any ideas, leads, info.
--
------
Mr. P.V.'d (formerly Droll Troll), Yonkers, NY

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entropic3.14decay at optonline2.718 dot net; remove pi and e
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[Will Brink]

In article <o5c9h.86$UA5.16@newsfe09.lga>, "Proctologically
Violated©®" <entropic3.14decay@optonline2.718.net> wrote:

> All,
>
> Some of you may be aware of creatine being a relative
> newcomer to the sports supplement field, and it seems to
> have garnered some credibility, among diehard weight
> lifters, at least, sort of like carb loading for
> marathoners.
>
> But here's the problem: I was looking at the Merck, and it
> states that in acid solution, conversion to creatinine is
> complete. And creatine ---> creatinine (cyclization) is
> irreversible. Even in neutral/alkaline solutions,
> creatine/creatinine equilibbriums are achieved, altho no K
> is specified.

Let's try this again. Here is some info from a recent report:

Creatine/ Creatinine

The speed of degradation is: · not depending on the
concentration · depending on the pH (the lower the pH the
faster the degradation) · depending on the temperature (the
higher the temperature the faster the degradation)

Figure 1. Degradation of Creatine at 25°C, after 0.5h, 4h, 8h,
1d, 2d, 3d at different pH values (7.5, 6.5, 5.5, 4.5, 3.5).

Creatine in aqueous solution is reasonably stable for up to 8h
at 25°C, pH
7.5 or 6.5. Breakdown

after 3 days at pH 5.5, 4.5 and 3.5 was 4%, 12% and 21%
respectively.

If Creatine is not used immediately after it is dissolved in
water it should be stored at a low temperature to slow down
the degradation.

The solubility of Creatine Monohydrate is 14 g per liter at
25°C (1.4%) and 8.5 g at 4°C.

>
> Creatine (open chain) is transported into the muscle,
> for phosphorylation. But, cyclized, it can only be
> excreted, and, being irreversible, cannot be re-opened
> for possible use.
>
> So how, then, is dietary creatine shown to be effective, and
> according to some citing studies, proven to increase muscle
> creatine/creatine phospate?

See above. Just because a reaction can take place, does not
mean it's spontaneous or instantaneous. Creatine does not
undergo spontaneous conversion to creatinine, thus why studies
show ingestion of creatine increases CP in tissues
efficiently.

>
> It seems that the Merck is not prone to hyperbole,

It's not an issue of hyperbole, it's an issue of them simply
stating that creatine can undergo conversion to creatinine
without actually giving the time table and conditions needed
for it to happen.

> so I am assuming the cite of complete conversion to be
> true--and am also assuming it to be fairly rapid, esp. in a
> pH 2 environment, like the stomach.

Yes on the first and no on the second. 3 days at PH 3.5 found
a 21% conversion. If the creatine sat in your stomach for days
on end at body temp and Ph of 2, you would see some conversion
no doubt, but that is not the case of course. For example:

8. Vanakoski J, Kosunen V, Meririnne E, Seppala T. Creatine
and caffeine in anaerobic and aerobic exercise: effects on
physical performance and pharmacokinetic considerations.
Int J Clin Pharmacol Ther. 1998 May;36(5):258-62.

"Creatine was rapidly and efficiently absorbed, as reflected
by plasma concentrations."

9. M. Francaux, et.al. Effect of Exogenous Creatine
Supplementation on Muscle PCr Metabolism Int J Sports Med;
10:139-145

"Following a single dose of creatine (5g), plasma creatine
rises rapidly peaking one or two hours after the ingestion.
Then it decreases to return to basal values within 8 hours
after intake (unpublished data)."

>
> TIA for any ideas, leads, info.

See above. Take home from the above is, creatine should be
ingested within a few hours of mixing into liquids. If not
ingested right away, put in the fridg. Leaving for weeks on
end is a no no.I hope that answers your questions and or gets
you headed in the right direction. Why didn't you start with
this perfectly reasonable post on MFW to begin with?