Fig. 1

Organization of the circadian clock within the hypothalamic–pituitary–ovarian axis. Afferent neuronal tracts of the photosensitive ganglion cells of the retina convey light–dark input to the SCN, composing the endogenous molecular clock. The circadian clock works at the HPG axis by means of transcription and translation feedback loops to convey temporal signals to organs and tissues to carry out vital homeostatic functions. The Clock-Bmal1 dimer activates the transcription of Clock-related genes, the products of which mediate various reproductive processes