The importance of plasma 3,4-dihydroxyphenylglycol (DOPEG) in analyses of the sympathetic nervous system in vivo.

In the anaesthetized rabbit, plasma DOPEG was used as a tool to estimate both, the total-body rate of neuronal re-uptake of noradrenaline (NA) and the factor F by which the NA concentration in the synaptic cleft exceeds that in plasma. The NA re-uptake rate was 3.5 times higher than the rate of NA net release into plasma and amounted to 863 pmol kg-1 min-1. F was 3.4. In a study in humans it was found that essential hypertension appears to be associated with an enhanced formation of that part of DOPEG which originates from NA leaking out of the transmitter storage vesicles.