Uptake of noradrenaline by human erythrocytes.
If human red cells are incubated with either noradrenaline or isoprenaline, these catecholamines are adsorbed to the cells surface first in a fast reaction. In a second, slower reaction they enter the cell membrane and are accumulated against the concentration gradient by the cells. It is supposed that the catecholamines enter the cells by simple diffusion and that they are reversibly bound to hemoglobin within the cells. It is  possible that this binding plays an important role in the transport of catecholamines in the blood stream where, it is assumed, they are protected from oxidation.
D004058:Diffusion; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000097:blood*; D011485:Protein Binding; D013696:Temperature; D013997:Time Factors
D006454:Hemoglobins; D009638:Norepinephrine