The basal level of PDE9a is responsible for maintaining the meiotic arrest, and the increased level of PDE9a induced by LH signaling is helpful for stimulating meiotic maturation by hydrolyzing cGMP in oocytes meds similar to doxycycline Isoflavones are a subclass of the flavonoids, which are found almost exclusively in soybeans and in a few other legumes including red clover