Plasma and whole blood taurine concentrations respond differently to taurine supplementation (humans) and depletion (cats).

In the present study the relationship between plasma and whole blood taurine was examined under normal physiological circumstances in humans and cats. In addition, the effect of taurine supplementation on plasma and whole blood taurine was evaluated in humans and the depletion of taurine pools after a taurine-deprived diet was studied in cats. The normal plasma taurine concentration in humans was 44 +/- 8 mumol/L and the whole blood taurine concentration was 227 +/- 35 mumol/L. Under normal physiological conditions plasma and whole blood taurine were not correlated (r = 0.092). Plasma taurine responded rapidly to dietary supplementation in humans or the taurine depletion in cats. In contrast, the whole blood taurine pool was more inert and varied only under extremes of depletion (cats) or sustained taurine supplementation.