Effects of Escherichia coli lipopolysaccharide on nitrate synthesis and on nitrosation of proline in rats.
Male Ola:SD rats were fed purified diets containing 5 or 20% lactalbumin as the protein source, with or without concomitant administration of Escherichia coli lipopolysaccharide (50-250 micrograms/kg, ip), and changes in 24-hr urinary nitrate excretion, plasma urea, plasma-nitrate pool size and 24-hr urinary nitrosoproline excretion were measured. Urinary nitrate and urinary 14C-nitrosoproline excretion (after oral [14C]proline administration) were significantly greater for rats receiving the high-protein diet compared with those on the low-protein diet. The co-administration of lipopolysaccharide increased nitrate excretion in both diet groups (although the increase was greatest (relatively) in the animals fed 5% lactalbumin), but did not significantly alter urinary nitrosoproline excretion by either group. Plasma urea concentrations and plasma-nitrate pool size were increased by a high-protein diet and/or lipopolysaccharide administration. These findings suggest that treatments which alter the availability of nitrate in vivo are not necessarily associated with increased nitrosation of proline.
Mallett
A K
AK
British Industrial Biological Research Association, Carshalton, Surrey, UK.
Walters
D G
DG
Ward
F
F
Farmer
P B
PB
Rowland
I R
IR
D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D004926:Escherichia coli; D007768:Lactalbumin / Q000008:administration & dosage; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009566:Nitrates / Q000097:blood / Q000378:metabolism* / Q000652:urine; D015538:Nitrosation / Q000187:drug effects; D011392:Proline / Q000378:metabolism*; D051381:Rats
D004044:Dietary Proteins; D008070:Lipopolysaccharides; D009566:Nitrates; D007768:Lactalbumin; D011392:Proline