Hormone changes in peripubertal girls.

CONTEXT: Studies of hormone changes in the peripubertal period note increases in adrenal hormones prior to increases in sex steroids. It is unclear how these processes are related to each other, except through this temporal relationship.
OBJECTIVE: Examine relationships in adrenal and sex hormones in 252 peripubertal girls. SETTING AND
DESIGN: Longitudinal observation study. School districts, at the Cincinnati site of the Breast Cancer and the Environment Research Centers, between 2004-2010. Participants were recruited between ages 6 and 7 years of age and were seen every 6 months. Main outcome measures included height, weight, maturation status, and fasting blood specimen. Serum was analyzed for selected hormones every six months, beginning 30 months prior to, and extending to 6 months after, breast development. Androstenedione, estradiol, estrone, and T were measured by high-performance liquid chromatography (HPLC) with tandem mass spectrometry. Dehydroepiandrosterone-sulfate (DHEA-S) and SHBG also were measured.
RESULTS: DHEA-S concentrations increased 24 months before breast development; androstenedione and estrone between 12 to 18 months before breast development; whereas estradiol and T increased, and SHBG fell between 6 and 12 months before breast development. Girls with greater body mass index had lower estradiol concentrations at onset of breast development as well as 6 months after pubertal onset.
CONCLUSIONS: Serum estrone and DHEA-S increased prior to estradiol concentrations, and the increase in estradiol occurred prior to breast development. Heavier peripubertal girls have lower estradiol levels at puberty, suggesting peripheral conversion of adrenal androgens to estrone.