P-31-nuclear magnetic resonance spectroscopy of blood: A species comparison

P-31-nuclear magnetic resonance (NMR) spectroscopy is frequently used as a tool in the study of organs from various animal species and humans. Because signals arising from the presence of blood are visible in in vivo P-31-NMR spectra of blood-filled organs, such as the heart, it is necessary to corr ect these spectra for the contribution of blood to the signal. If is unknow n whether species differences in P-31 signals of blood exist. P-31-containi ng metabolites of blood from various species were therefore quantified by m eans of P-31-NMR spectroscopy. Signals of 2,3-bisphosphoglycerate (2,3-DPG) ; phosphodiesters (PDE); and gamma-, alpha-, and beta-ATP were detected in all P-31-NMR spectra of blood. 2,3-DPG/ATP ratios were significantly higher in dogs, rats, and guinea pigs than in humans but lower in sheep. Pig and rabbit were the only animals with a 2,3-DPG/ATP ratio similar to that of hu mans. PDE levels varied among species but were significantly lower than in humans only in guinea pigs. The PDE/ATP ratio was relatively similar among all species compared with humans, except dog and guinea pig, where it was s ignificantly higher and lower, respectively. We conclude that because of la rge species differences, species-specific P-31 metabolite ratios should be applied for the correction of in vivo P-31-NMR spectra.