[Several pattern in the synthesis and uptake of H3-catecholamines by isolated rat vas deferens]

In the rat isolated vos deferens, increase of the thyrosine-H3, DOPA-H3, and Dopamine-H3 contents in the incubation medium increases respectively Km and Vmax of the noradrenaline-H3 biosynthesis. Increase of the Dopamine-H3 and noradrenaline-H3 in the medium also increases Km and Vmax of neuronal uptake and reservation of these catecholamines in the adrenergic granules. The simultaneous increase of Km and Vmax of the catecholamines synthesis and uptake leads to that the effectiveness of these processes undergoes much lesser alteration that the main parametres. The interrelationship between the substrate concentration in the medium and the velocity of catecholamines synthesis is, apparently, due to that the adrenergic granules differ from each other by the intensity of synthesis and reservation of noradrenaline. This is one of the factors regulating accumulation and release of the sympathetic mediators.