Clock control of mammalian reproductive cycles: Looking beyond the pre-ovulatory surge of gonadotropins.

Clock control of mammalian reproductive cycles: Looking beyond the pre-ovulatory surge of gonadotropins. Rev Endocr Metab Disord. 2019 Dec 12;: Authors: Silva CC, Domínguez R Abstract Several aspects of the physiology and behavior of organisms are expressed rhythmically with a 24-h periodicity and hence called circadian rhythms. Such rhythms are thought to be an adaptive response that allows to anticipate cyclic events in the environment. In mammals, the circadian system is a hierarchically organized net of endogenous oscillators driven by the hypothalamic suprachiasmatic nucleus (SCN). This system is synchronized by the environment throughout afferent pathways and in turn it organizes the activity of tissues by means of humoral secretions and neuronal projections. It has been shown that reproductive cycles are regulated by the circadian system. In rodents, the lesion of the SCN results on alterations of the estrous cycle, sexual behavior, tonic and phasic secretion of gonadotropin releasing hormone (GnRH)/gonadotropins and in the failure of ovulation. Most of the studies regarding the circadian control of reproduction, in particular of ovulation, have only focused on the participation of the SCN in the triggering of the proestrus surge of gonadotropins. Here we review aspects of the evolution and organization of the circadian system with particular focus on its relationship with the reproductive cycle of laboratory rodents. Experim...
Source: ENDOCR REV - Category: Endocrinology Authors: Tags: Rev Endocr Metab Disord Source Type: research