[Rates of endogenous noradrenaline release in rat brain, heart and intestines: comparison of results obtained after biosynthesis inhibition and 3H-tyrosine labeling].

After labelling of noradrenaline stores with tyrosine 3H, the rate constant of NA efflux was calculated from the change of the NA-3H and TY-3H specific activities. The biological half-life of NA was 2,2 h in the brain, 24 h in the heart and 3,3 h in the intestine. These values were similar to those obtained after inhibition of NA synthesis by alpha-methylparatyrosine.