KINETICS AND SOME CHARACTERISTICS OF UPTAKE OF NORADRENALINE BY THE HUMAN UMBILICAL ARTERY

Abstract

The uptake of exogenously added noradrenaline (NA) (0.5‐2.5 μg/ml) by the human umbilical artery was linear with time up to 10 minutes. The uptake was saturable and could be described by the Michaelis‐Menten equation. The uptake was cocaine‐resistant, normetanephrine‐sensitive, was considerably inhibited in the cold and was partially inhibited by Na+ ‐ deficiency. Of NA accumulated in the artery 31% could be washed out by NA‐free medium. It is concluded that the mechanism of uptake of NA by the human umbilical artery is similar to the uptake2 mechanism. 1975 British Pharmacological Society