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. Author manuscript; available in PMC: 2015 Sep 8.
Published in final edited form as: Fertil Steril. 2013 Mar 6;100(1):23–38. doi: 10.1016/j.fertnstert.2013.02.011

FIGURE 4.

FIGURE 4

Preovulatory follicles. The hallmarks of preovulatory follicles are the induction of LH receptors (LHCGR) and elevated expression of aromatase (CYP19A1). In obese individuals with PCOS, preovulatory follicles that are selected and ovulate (either in response to weight reduction, exogenous hormone, and/or metformin) express high AMH and remain hyperandrogenic. Thus, despite lowered insulin action or improved adipogenic function to facilitate the growth of follicles that can be ovulated, theca androgen production is central to the PCOS condition. However, direct effects of insulin and/or androgens may harm oocytes at this late stage or earlier stages of follicular development. Oocyte factor and GDF9 signaling is denoted by green arrows; LH and androgen signaling by red arrows and letters; and insulin signaling by purple arrows.