Increased follicular fluid total and free cortisol levels during the luteinizing hormone surge

Abstract

To determine the changes in follicular fluid (FF) total and free cortisol during the LH surge in naturally ovulating women. Twenty-six women having diagnostic laparoscopy during the follicular phase of normal menstrual cycles were selected. Blood samples were collected 1 day before, the day of, and 1 day after surgery and the results of serum E2 and LH were used to divide the cycles retrospectively into pre- and post-LH surge groups. Follicular fluid was collected during laparoscopy. Serum P, total and free cortisol, and FF volume, E2, P, total cortisol, and free cortisol were measured on the day of surgery. Median serum and FF P levels were significantly higher in the post-LH surge group compared with the pre-LH surge group (0.54 versus 1.54 ng/mL [1.7 versus 4.85 nmol/L] and 5.03 versus 28.0 micrograms/mL [15.8 versus 88.0 mumol/L], respectively). Follicular fluid volume also increased significantly after the surge (2.5 versus 4.5 mL). Median serum total and free and percent free cortisol were higher after the surge, although not significantly. In contrast, FF total, free, and percent free levels increased dramatically between pre- and post-LH surge samples (4.41 versus 43.6 ng/mL [16.0 versus 158 nmol/L], 0.138 versus 6.68 ng/mL [0.5 versus 24.2 nmol/L], and 3.3% versus 15.0%, respectively; P < 0.05). An increase in total and free cortisol occurs in the follicle during the LH surge. Cortisol and its regulation by 11 beta-hydroxysteroid dehydrogenase therefore may exert a physiologic role in oocyte maturation or ovulation.