Ovulation requires preovulatory surges of gonadotropin-releasing hormone (GnRH) from preoptic hypothalamic neurons, initiated by elevated ovarian estradiol (E₂). Rising estradiol activates a subset of sexually dimorphic kisspeptin (Kiss-1) neurons in the female, located in the anteroventral periventricular nuclei (AVPV). Conversely, estradiol negative feedback on GnRH secretion is mediated by a...
The endogenous circadian clock is an intracellular transcriptional feedback loop timing daily patterns of multiple biological rhythms within a 24-hour period. Disturbance in various rhythms leads to alteration of normal biological processes including cellular proliferation and tumor suppression. Endogenous circadian clock rhythms have been found to be disrupted in breast...