[Urinary catecholamine excretion in aging].
In ageing female subjects, the urinary noradrenaline excretion (UNA) is reduced with respect to the controls in young adults. On the other hand the ratio UNA/clearance of endogenous creatinine increases with ageing. This provides a confirmation of the fact that ageing is associated with an increase in plasma noradrenaline. The ratio UA/clearance of creatinine remains unaltered. So far the physiological meaning of these results remains unclear.