Beta-adrenoceptor changes in human lymphocytes, induced by dynamic exercise.

In 10 healthy volunteers the effects of acute increases in concentrations of catecholamines in plasma induced by dynamic exercise (on a bicycle for 15 min at 80% of maximum heart rate) on lymphocyte beta 2-adrenoceptor density (determined by (+/-)-125iodocyanopindolol binding) and -responsiveness (determined by cyclic AMP responses to 10 mumol/l isoprenaline) were investigated. Immediately after exercise plasma catecholamines were increased about 4-fold; concomitantly receptor density and cyclic AMP production increased 55% and 65%, respectively. One hour after exercise beta-adrenoceptor density and plasma catecholamines had reached values, which were not significantly different from pre-exercise values, while cyclic AMP production was significantly diminished. It is concluded, that acute increases in concentrations of catecholamines in plasma may increase beta-adrenoceptor density and - responsiveness in human lymphocytes.