Endocrine Abstracts

Many surveys have shown that children are ubiquitously exposed to endocrine disruptors (EDs) like bisphenol A (BPA) and phthalates, and many laboratory studies have shown these EDs have adverse effects related to hormone secretion, while the evidence on infants’ mini-puberty has not been observed yet. A prospective cohort was recruited at the early maternal pregnancy stage by the Maternal and Child Health and Family Planning Service Center, Daishan, China, from March 2012 to December 2014. After delivery, the mothers offered their baby (0–6 months old) urine samples collected by the disposable diapers. Urinary BPA, phthalate metabolites, estradiol (E₂), testosterone (T), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and creatinine were analyzed, respectively. The partial correlation and multivariable linear regression were applied to assess the associations of endocrine disruptors with E₂, T, FSH and LH for each of the development stages, i.e., the newborn, 14-days, 28-days, 42-days, 3-months and 6-months, respectively. Firstly, urinary hormones showed the clear surge profiles for the selected hormones during mini-puberty; in addition, the endogenous creatinine releasing was increased with the growth of baby. After adjusted by creatinine, maternal age, end-of-pregnancy weight, parity, smoking, delivery mode and infant body mass index (BMI), BPA was positively associated with E₂ both in male (for 14-, 28- and 42-days stages) and female (for 14-, 28-, 42-days and 3-months stages) infants, positively associated with E₂/T ratio both in male (for 14- and 28-days stages) and female (for 14-days stage) infants, positively associated with T in female (for 3-months stage). To phthalates, their metabolism also changed, in which the di-ester phthalates’ hydrolysis may be decreased but the 2nd β-oxidation of the middle and long side chains of the mono-ester phthalates was increased. After adjusted by maternal age, end-of-pregnancy weight, parity, smoking, delivery mode, gender and BMI of infants, some interesting associations were also observed between the phthalate exposure and mini-puberty hormone surges. By using a time-series sampling strategy, this study investigated the early infantile life-stage associated endocrine disrupting of phthalates and BPA to some selected hormones by using urine from diapers. The results showed that the phthalate metabolism in infantile body is changed along with the growth. In addition, the infants’ first show of steroids’ surge after leaving the maternal uterus steroidogenic environment (i.e., mini-puberty) may be affected by EDs, which disrupt the premature gonad function at some special development windows.