ABSTRACT
The hormonal control of ovarian function by gonadotropins plays a key role in the physiologic process of follicular growth and differentiation. Over the last decade, the respective contributions of FSH and LH to follicular development have been better defined mainly through clinical data obtained from assisted reproduction technology (ART) cycles performed with GnRH agonist protocols. More recently, the introduction of GnRH antagonists to prevent the LH surge has provided a new model for assessing the respective roles of FSH and LH. In every situation, measurements of plasma FSH and LH levels were used to evaluate the endocrine environment of the follicle. While it is clear that hormonal assays from blood sampling cannot adequately reflect the biologic activity of gonadotropins, this approach has allowed an assessment of the required supply of exogenous FSH and LH in ART cycles.
