Ovarian folliculogenesis is characterized by drastic proliferation and differentiationof granulosa and theca cells. The uterus is closely synchronized to the ovary: increasedovarian steroids regulate the uterus as one of the principal targets to prepare embryonicimplantation following fertilization. In rodents, the endometrial stoma cells undergoproliferation and decidualization in response to ovarian steroids and embryonicimplantation at the early stage of pregnancy. Cellular functions in the ovary and uterusare accompanied by cyclic changes of cell proliferation, differentiation and apoptosis.The clock system may contribute to the progress of follicular development, luteinizationand luteolysis, and ovarian steroid-induced proliferation and differentiation of uterus cellsthrough fluctuating hormones. Recently, there is a growing body of evidence that thecircadian clock genes are expressed in reproductive tissues including the ovary anduterus. The clock genes such as Periods are differently expressed in heterogeneous celltypes of the ovary and uterus. The hormonal regulation of circadian clockworks inovarian and uterus stoma cells is mentioned in the present review. The circadianpacemaker was altered in ovarian and uterus cells during cell differentiation andapoptosis. Progesterone might play a pivotal role in the circadian oscillator of the uterusendometrial stoma cells. However, the Per2 circadian oscillation was down-regulated inuterus endometrial stoma cells during decidualization, even though serum progesteronelevel is high at this stage. Thus, alteration of the circadian pacemaker results largely fromhormonal inputs such as gonadotropins and ovarian steroids, but cell differentiation alsodisrupts the circadian pacemaker.
|Title of host publication||Circadian Rhythms: Biology, Cognition and Disorders|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||16|
|Publication status||Published - Mar 2012|
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