Role of Estrogens in Ovarian Dysfunction and Fertility. Options for New Therapies with SERMs

Estrogens represent the key ovarian hormone produced by the developing preovulatory follicle. Serum concentrations start to rise from the midfollicular phase onwards, coinciding with the visualization of the dominant follicle upon ultrasound. Estrogens are synthesized by aromatase activity of the granulosa cells and secreted into the follicular fluid compartment, where 1,000-fold higher levels can be observed. Its significance for oocyte maturation and fertilizing potential remains unknown.