STUDIES ON OESTROGEN METABOLISM IN INFANTS AND CHILDREN

ABSTRACT The urinary excretion of oestrone (3-hydroxy-oestra-1,3,5(10)-triene-17-one), 17β-oestradiol (oestra-1,3,5(10)-triene-3,17β-diol) and oestriol (oestra-1,3,5(10)-triene-3,16α,17β-triol) was studied in infants and children before and after the intramuscular injection of 17β-oestradiol and oestriol, respectively. No measurable amounts of these oestrogens could be detected in the urine specimens collected during the pre-treatment period. Administration of 500 μg of 17β-oestradiol in oil to infants of 2 to 10 months of age did not give rise to measurable amounts of urinary oestrone or oestradiol; there was, however, a limited increase in oestriol excretion, corresponding to approximately 2 per cent of the administered dose. When the same amount of 17β-oestradiol was administered to children aged 2.5 to 9 years, significant amounts of oestrone + oestradiol (corresponding to 3.5 % of the administered dose) were excreted in the urine in addition to considerable amounts of oestriol (approximately 6 % of the administered dose). Following the administration of 500 μg of oestriol in oil to infants and children (2 to 36 months of age) only some 14 % of the administered oestriol could be recovered from the urine and only 2 % from the faeces. It is concluded that the intermediary metabolism of 17β-oestradiol in infants is significantly different from that of adults. It is suggested that some time during the second year of life the oestradiol metabolism assumes the adult type. It is also suggested that – in contradistinction to the situation in the adult – in infants and young children oestriol does not represent a final stage in oestrogen metabolism, but rather an intermediate one, and that certain aspects of the oestrogen metabolism do not assume the adult type before the fourth year of life, or perhaps later.