Long-term exposure to estrogens increases the incidence of gynecologic cancers (breast, ovarian, and endometrial cancers) in humans. During the carcinogenic processes, estrogens acquire DNA-damaging activity via metabolic activation. Our group has studied the carcinogenic mechanisms of estrogens using an animal model for estrogen-induced breast cancer. To understand the precise mechanisms, it is quite essential to measure the metabolic profile of estrogens. In this study, we developed a rapid

more »

... d simultaneous quantification method for three estrogens (estrone, E1; 17ß-estradiol, E2; 17α-estradiol, αE2) using a high-resolution mass spectrometer equipped with ultra-high-performance liquid chromatography (UHPLC-MS). Methods: UHPLC-MS analysis of E1, E2, and αE2 was performed on a quadrupole time-of-flight MS (Triple TOF6600) and UHPLC (Nexera XR). Estrogens were quantified using a high-resolution multiple reaction monitoring as follows: E1 (m/z 269.1>145.069), E2/αE2 (m/z 271.1>145.069). Results and discussion: Our method achieved a fast analysis (run time, 5 min), and good sensitivity and linearity as follows: E1 (1-1000 pg/mL, r 2 =0.9987), E2 (2-1000 pg/mL, r 2 =0.9991), αE2 (1-1000 pg/mL, r 2 =0.9989). Recovery test using a charcoalstripped serum spiked 10-1000 pg/mL of estrogens showed a suitable recovery efficiency from 85.6% to 106.6%. Since the serum level of estrogen ranges from several to several hundred pg/mL, our method would be applicable for direct measurement of estrogen profiles without chemical derivatization.