Re: Research regarding kidney failure: I´m perplexed

> The urea level or BUN is used as a measure of glomerular filtration under
> normal circumstances.  Renal failure is not caused by elevated urea but the
> other way around. 

Yes, I know. Maybe I wasn´t clear enough. I understood that some
people are studying polar bears´ metabolism to understand *how* they
survive for months without urinating (clearing their systems of
metabolic wastes) and aren´t poisoned by their own metabolic wastes.
And then my doubt was: if they are burning only fat and fat does not
result in anything but water and CO2, why do they think the polar
bears' metabolism is performing some miracle?

> There are other waste products produced by daily
> metabolism that are toxic to the body and need to be excreted by the body
> and BUN is an easy marker for this.

What would these waste products be? These animals are not eating, they
are only burning fat.

> The cholesterol system in these bears is also interesting so in short they
> are two different species but the study of one might lead to a temporary
> relief in the other.

Do you know of any texts discussing their cholesterol system on the
net? I´d like to read about it. Thanks. :)