Sex-differences in catecholamine metabolites in human urine during development and at adulthood

Abstract

Adrenergic amines (dopamine [DA], norepinephrine [NE], epinephrine [E] and related compounds (DOPA, 3-methoxytyramine [MT], normetanephrine [NMN], metanephrine [MN], 3-5-dihydroxyphenylacetic acid [DOPAC], vanilmandelic acid [VMA] were analyzed in urine of human from one day to 40 years of age, in view to investigate the sex influence on catecholamine metabolism during life. In neonatal life (1 day to 3.5 months), the total amounts of urinary (E + MN) and (NE + NMN + VMA) were lower in girls than in boys, the former two compounds being mainly of adrenal medullary origin and the latter three coming largely from the sympathetic neurons. In adulthood, women excreted epinephrine (12.5 +/- 2.2 micrograms/24 hours) at lower levels then men (22.8 +/- 4.5 micrograms/24 hours) but no sex related differences occurred in the total amounts of urinary E + MN and NE + NMN + VMA. It is concluded from our study that, during the neonatal life, girls exhibit a lesser adreno-sympathetic maturity than boys, but full maturation of peripheral adrenergic sites is reached near to the fifth year of age in both sexes. The role of testosterone has been discussed. In adults, the lower epinephrine levels found in women urine do not seem to result from a sex difference in the degree of adrenergic maturity, but perhaps partly from an increased rate of epinephrine inactivation by catechol-O-methyltransferase.