[sufler (OP)]

Hi.
I know that high urates can cause severe kidney damage, mostly by deposition of crystals in the organ or by increasing blood pressure in the small vessels. Yet what is the exact link between a pre-existing kidney damage which in turn increases plasma uric acid levels? This has been bothering me for several days and having read a bunch of articles didn't help me to make it out.

As I determined, uric acid is completely filtered through glomellular filtration and then  the kidney puts most of its efforts in reabsorbing uric acid in the tubules, rather than excreting it. So it would seem logical that plasma urates should decrease in renal dysfunction since the reabsorbing machinery would gradually fail to do its job. And in turn, the urine urates should increase because most of the metabolite would be lost.

However a lab diagnostics book I have, actually mentions only one kidney disease that increases plasma uric acid, and that is the genetic condition - polycystic kidney. Yet there is a bunch of kidney conditions (like glomerulonephritis) proposed as the cause of decreased urates in the urine...  And here I get pretty confused because, if glomerulonephritis decreases urine uric acid but does not apparently increase its plasma levels, so where does the uric acid go in this and related conditions??