The involvement of suprachiasmatic nuclei in the regulation of estrous cycles in rodents.

Originally suprachiasmatic nuclei (SCN) were considered the main center of signals regulating the cyclic function of female reproduction, especially the gating of the LH surge. It was confirmed in the rat but not in the hamster. Some recent data show that multiple and complex interactions and processes underlie the occurrence of this very important and crucial event in female reproduction: the LH surge. Thanks to such multiway and multifactor control, the LH surge and the resulting ovulation occur regularly when "the time window" opens. Involvement of the SCN and other nuclei of the respective area in the regulation of rhythmic reproductive phenomena in female rats and hamsters is discussed.