N-Methyladrenaline: age-dependent urinary excretion, perinatal organ content and relation with ‘classical’ catecholamines

Using high performance liquid chromatography with electrochemical detection we determined free dopamine, noradrenaline, adrenaline and N-methyladrenaline in: (1) urines from newborns ( n = 32), children ( n = 45) and adults ( n = 19) and (2) adrenals, organ of Zuckerkandl, dorsal roots and perirenal brown adipose tissue from deceased fetuses ( n = 2), very premature ( n = 6) and term ( n = 2) newborns and infants ( n = 2). Data from children and adults showed that contributions of adrenaline and N-methyladrenaline to the sum of urinary free catecholamines increase with age. Relative amounts of adrenaline and N-methyladrenaline increased in both adrenal and extra adrenal chromaffin tissues from late gestation up to several months of postnatal life. Increase of adrenal N-methyladrenaline content follows endocrine maturation of the medulla, phenylethanolamine- N-methyltransferase induction and subsequent adrenaline synthesis. Relative amounts of N-methyladrenaline in extra adrenal chromaffin tissue increase in a period that is associated with its regression. Further investigations are necessary to elucidate the function and possible clinical chemical usefulness of N-methyladrenaline.