Traditional Sex Steroids and Ketoandrogen Levels by Menstrual Cycle Stage, Age and Body Mass Index in Women Aged 18-39 Years

Background

Prior studies suggest that testosterone (T), androstenedione (A) vary across the menstrual cycle and decline with age in young women. Little is known about the recently described ketoandrogens with respect to the menstrual cycle or age. The levels of C19 steroids in premenopausal women need to be established using liquid chromatography, tandem mass spectrometry (LC-MS/MS).

Aims

To determine levels of the unconjugated C19 steroids, including 11ketoandrostenedione (11KA) and 11 ketotestosterone (11KT), in premenopausal women by LC-MS/MS, and report changes with menstrual cycle stage, body mass index and age.

Methods

The Grollo-Ruzzene Study was of a representative sample of women aged 18-39 years, from the 3 eastern, most populous, states of Australia, of which 602 cycling women provided a blood sample for this analysis. Participants were representative of the Australian population¹ with 73% Caucasian, 2% indigenous, 15% Asian and 10% other.

Samples were collected by Sonic pathology and serum aliquots stored at -80C until analysis. Sex steroids were analysed by LC-MS/MS.

Participants reported the number of days since the start of their last menstrual period (LMP) at blood draw. Cycle phase was classified as ‘early follicular’ (days 1-7), ‘mid-cycle’ (days 8-21), ‘luteal’ (days 22-35 or ‘>35 days since LMP/unknown’). Any woman who had a serum progesterone level ≥ 12 nmol/L was classified as luteal phase.

Summary

SEX STEROIDS IN PREMENOPAUSAL WOMEN

• Estradiol (E₂), Estrone (E₁), T, A and SHBG vary across the cycle (11KT, 11KA and DHEA do not)
• 11KT & 11KA are stable across the menstrual cycle indicating they are not arising from ovarian precursors
• T, A, 11KT, 11KA and DHEA decline across the reproductive years

This study provides reference values by cycle stage and age for each measured hormone.