X-Message-Number: 24748
Date: Sun, 3 Oct 2004 10:45:59 -0700 (PDT)
From: Doug Skrecky <>
Subject: dietary change reduces pyrraline excretion by 94%

Biochem Soc Trans. 2003 Dec;31(Pt 6):1383-5.
Glycation in food and metabolic transit of dietary AGEs (advanced
glycation end-products): studies on the urinary excretion of pyrraline.
 Pyrraline [epsilon-(2'-formyl-5'-hydroxymethyl-pyrrolyl)-L-norleucin]
belongs to the group of AGEs (advanced glycation end-products) formed in
the final stage of the Maillard reaction in foods and in vivo. As it is
generally accepted that AGEs are pathophysiologically relevant in aging
and in diseases such as diabetes and uraemia, physiological consequences
resulting from the ingestion of dietary AGEs are discussed, but balance
studies for well defined AGEs are still lacking. The aim of our study was
to investigate the influence of nutrition on the urinary excretion of
pyrraline. After the first day without dietary restrictions, seven healthy
volunteers were asked, starting on the morning of day 2, to ingest a diet
virtually free of Maillard compounds (i.e. no cooked or roasted foods, no
bakery products, no coffee, etc.). Dietary control was stopped on the
morning of day 5. We collected 24 h urine samples for these 5 days, which
were analysed for free pyrraline by reverse-phase HPLC with UV detection
at 297 nm. We found that urinary excretion of free pyrraline was directly
affected by the composition of the diet, decreasing from 4.8+/-1.1 mg/day
on day 1 to levels of 1.6, 0.4 and 0.3 mg/day on days 2, 3 and 4
respectively, followed by a significant increase to 3.2+/-1.4 mg/day on
the 5th day. The results of this work prove, for the first time, that
urinary excretion of pyrraline is strongly dependent on its dietary
intake. Thus the influence of nutrition should be taken into consideration
in studies directed to the physiological role of glycation compounds.

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