OBJECTIVE: The mechanism of dominant follicle selection remains obscure. We have investigated the association between follicle diameter and follicular steroid levels in individual human ovarian follicles throughout the menstrual cycle. DESIGN: Fluid from ovarian follicles (n = 326) was obtained in vivo during surgery from 55 regularly cycling women with proven fertility. Follicles were divided into dominant (diameter >9 mm, n = 45) and non-dominant (diameter < or = 9 mm, n = 281) based on ultrasound measurements. MEASUREMENTS: Fluid was assayed for oestradiol (E2), androstenedione (AD), and progesterone (P). RESULTS: Median P and E2 levels were significantly lower (P < 0.0001) and AD levels significantly higher (P = 0.03) in non-dominant as compared to dominant follicles. In non-dominant follicles AD (r = 0.14, P = 0.02), but not P and E2, levels were correlated to follicular diameter, and significant changes in steroid concentrations across the menstrual cycle were absent. In dominant follicles, diameter was positively correlated with P and E2 (P < 0.001) levels, and inversely correlated with AD concentrations (P = 0.01). CONCLUSIONS: Results indicate that (1) intrafollicular oestradiol concentrations rise only in follicles exceeding 9 mm in diameter and correlate with the diameter of these dominant follicles, suggesting that significant increase in aromatase enzyme activity occurs only in the dominant follicle (2) a cycle-independent accumulation of androstenedione with size occurs in non-dominant follicles, and (3) progesterone production occurs in the largest dominant follicles only, suggesting a limited, if any, role for progesterone during follicle development.
OBJECTIVE: The mechanism of dominant follicle selection remains obscure. We have investigated the association between follicle diameter and follicular steroid levels in individual human ovarian follicles throughout the menstrual cycle. DESIGN: Fluid from ovarian follicles (n = 326) was obtained in vivo during surgery from 55 regularly cycling women with proven fertility. Follicles were divided into dominant (diameter >9 mm, n = 45) and non-dominant (diameter < or = 9 mm, n = 281) based on ultrasound measurements. MEASUREMENTS: Fluid was assayed for oestradiol (E2), androstenedione (AD), and progesterone (P). RESULTS: Median P and E2 levels were significantly lower (P < 0.0001) and AD levels significantly higher (P = 0.03) in non-dominant as compared to dominant follicles. In non-dominant follicles AD (r = 0.14, P = 0.02), but not P and E2, levels were correlated to follicular diameter, and significant changes in steroid concentrations across the menstrual cycle were absent. In dominant follicles, diameter was positively correlated with P and E2 (P < 0.001) levels, and inversely correlated with AD concentrations (P = 0.01). CONCLUSIONS: Results indicate that (1) intrafollicular oestradiol concentrations rise only in follicles exceeding 9 mm in diameter and correlate with the diameter of these dominant follicles, suggesting that significant increase in aromatase enzyme activity occurs only in the dominant follicle (2) a cycle-independent accumulation of androstenedione with size occurs in non-dominant follicles, and (3) progesterone production occurs in the largest dominant follicles only, suggesting a limited, if any, role for progesterone during follicle development.
Authors: Ziad R Hubayter; Vaishali Popat; Vien H Vanderhoof; Obioma Ndubizu; Diane Johnson; Edie Mao; Karim A Calis; James F Troendle; Lawrence M Nelson Journal: Fertil Steril Date: 2009-11-25 Impact factor: 7.329
Authors: MaryFran R Sowers; Huiyong Zheng; Daniel McConnell; Bin Nan; Siobán D Harlow; John F Randolph Journal: J Clin Endocrinol Metab Date: 2008-07-22 Impact factor: 5.958