Influence of genetic and environmental factors on serum estradiol and testosterone of twin girls

ObjectiveTo explore the change of serum estradiol(E2)and testosterone(T)concentrations throughout the puberty of girls and estimate the effects of genetic and environmental factors on serum E2 and T concentrations.Method The study population consisted of 180 pairs of twin girls aged 6 to 18 of whom.132 pairs monozygotic twins(MZ)and 48 pairs dizygotic twins(DZ),who were all from Qingdao city of Shandong province.Anthropometric measurement and pubertal development stage were determined by Tanner standard.Fasting serum E2 and T contents were assayed by Radioimmumo assay(RIA).ResultsSerum E2 and T concentrations increased from Tanner I toⅣand decreased later.E2 and T concentrations had substantial genetic variation,with additive genetic factors accounting for 40% and 47% of the total phenotypic variation,respectively.The heritabilities of E2 and T in post-menarche girls were greater than those of non-menarche girls.ConclusionSerum E2 and T concentrations of pubertal girls were influenced both by the genetic and environmental factors, and genetic influence on E2 was significant after menarche occurred.