THE INFLUENCE OF GENDER IN THE EVALUATION OF PLATELET AND PLASMA-CATECHOLAMINES

The platelet and plasma levels of catecholamines (CA) were simultaneou sly studied in a group of normal subjects in order to find possible se x-related changes in the distribution of CA in these two compartments. No significant differences between males and females were observed, b ut a marked platelet noradrenaline increase was found in the luteal ph ase as compared to the follicular phase. Furthermore, the platelet and plasma CA levels were strongly correlated in the male group but not i n the female group. These results, while confirming the existence of a menstrual-related variability in noradrenergic activity, suggest a se x-related difference in the dynamic balance between platelet and plasm a CA levels. The simultaneous assay of platelet and plasma CA enabled this phenomenon to be revealed, whereas the separate evaluation of pla telet or plasma CA levels would not have done so.