Abstract
Variable depletion of adrenal catecholamines was caused in rats by injections of reserpine and muscular work. The intensities of the chromaffin reaction, the iodate reaction and formalin-induced fluorescence in adrenal sections were measured by cytophotometry and compared with chemically determined concentrations of adrenaline and noradrenaline in the adrenal medulla. A close correlation was observed between the optical density of the chromaffin reaction and the total catecholamine concentration, as well as between the intensity of the formalin-induced fluorescence, the optical density of the iodate reaction and the noradrenaline concentration.