Menstrual cycle-related changes in blood serum testosterone and estradiol levels and their ratio stability in young healthy females

Abstract

The role of testosterone in females has not been fully elucidated. Studies usually involved postmenopausal women. Literature data on age-related changes of testosterone levels are contradictory. The application of sex hormones and their combination in medical practice increases the importance of study of the menstrual cycle fluctuations in testosterone, populational variability of testosterone and estradiol levels and their ratio in healthy females to prevent the excessive doses of sex steroids and provide the using of optimal their doses in different phases of menstrual cycle during treatment. The objective of our research was to evaluate testosterone and estradiol levels, their interrelation and their ratio in different stages of menstrual cycle in young healthy women. Twenty-two young Ukrainian females aged 18 to 22 years were enrolled in this study. Testosterone and estradiol levels in blood serum were determined by Estradiol ELISA and Testosterone ELISA kits (Italy). Both estradiol and testosterone levels depended on menstrual cycle phases. The highest testosterone level was revealed in ovulation. No correlation between blood serum testosterone and estradiol levels was found in all menstrual cycle phases. Differences in testosterone and estradiol levels between Ukrainian women and some other populations of women were noted, indicating that such differences must be taken into account when treating women of different populations. Testosterone/estradiol ratio was not changed during menstrual cycle. Because of the constancy of the ratio of testosterone to estradiol during menstrual cycle and the age-related change in that ratio, this must be taken into account in the treatment of elderly women in order to create a testosterone-estradiol ratio that is characteristic of young women.