Title: Nitrate biosynthesis in rats, ferrets and humans. Precursor studies with L-arginine.

Authors: Leaf, C D; Wishnok, J S; Hurley, J P; Rosenblad, W D; Fox, J G; Tannenbaum, S R

Published In Carcinogenesis, (1990 May)

Abstract: L-Arginine, the primary nitrogen source for nitric oxide synthesized by many cell types in culture and for biosynthesized nitrate in humans, is also a nitrogen source for biosynthesized nitrate in rats and ferrets. After administration of [15N2]L-arginine to rats and ferrets, [15N]NO3- was detected in urine. Escherichia coli lipopolysaccharide induced more than a 10-fold increase in urinary nitrate in rats and a parallel increase in incorporation of 15N from [15N2]L-arginine into NO3-. Bradykinin, a vasodilator which induces nitric oxide production by endothelial cells in vitro, lacked detectable effect on urinary nitrate or on incorporation of L-arginine nitrogen into nitrate in rats. A prolonged period of vasodilation brought on by an extended period of exercise increased urinary nitrate 2-fold in human subjects. In the rat, recoveries in 24 h post-dose urine collections of [15N]NO3- given i.v. and i.p. were 75 and 64% respectively, while in the ferret, recoveries of i.v. and per os [15N]NO3- doses were 49 and 34% respectively. Thus, nitrate synthesized by mammalian cells in vivo would undergo losses similar to those for exogenous nitrate.

PubMed ID: 2335012

MeSH Terms: Adult; Animals; Arginine/metabolism; Exercise/physiology; Ferrets; Humans; Injections, Intraperitoneal; Injections, Intravenous; Male; Nitrates/administration & dosage; Nitrates/metabolism*; Nitrogen Radioisotopes; Nitrogen/metabolism; Rats; Rats, Inbred Strains