Autophagy is a major cellular catabolic pathway tightly associated with cell survival. The involvement of autophagy in the prolonged survival of blastocysts in the uterus is well established, and it was assumed that ovarian steroid hormones – progesterone (P₄) and estrogens – have important roles in the regulation of autophagy. However, information is scarce regarding whether these hormones regulate autophagy in certain hormone-responsive cellular systems. In this study, we investigated the effects of estrogen and P₄ on autophagic response in the uteri of pregnant mice and in ovariectomized (OVX) mice treated with hormones. During pregnancy, autophagic response is high on days 1 and 2 when the uterus shows an inflammatory response to mating, but it subsides around the time of implantation. Dexamethasone treatment to day 1 pregnant mice reduced autophagy in the uterus. In OVX mouse uteri, estrogen or P₄ reduces autophagic response within 6 h. Glycogen content in OVX uteri was increased by 3-methyladenine treatment, suggesting that autophagy is involved in glycogen breakdown in the hormone-deprived uterus. The classical nuclear receptor antagonists, ICI 182 780 or mifepristone, lead to the recovery of the autophagic response in OVX uteri. The suppression of autophagy by 17β-estradiol is inversely correlated with the accumulation of phospho-mouse target of rapamycin, and rapamycin treatment is moderately effective in the upregulation of autophagic response in OVX mouse uteri. Collectively, this study establishes that the uterine autophagy is induced in hormone-derived environment and is suppressed by hormone treatment. Uterine autophagy may have multiple functions as a responsive mechanism to acute inflammation and as an energy provider by breaking down glycogen under hormone deprivation.

Etv4, Etv1, and Etv5 are members of Etv4 subfamily of E26 transformation-specific (Ets) transcription factors that are known to influence a host of biological processes. We previously showed that Etv5, expressed in Sertoli cells, plays a crucial role in maintaining spermatogonial stem cell niche in the mouse testis. However, it is not yet known whether Etv4 family members are expressed in the ovary or play any role in ovarian functions. Here, we show that Etv5 and Etv4 are expressed in mouse ovaries in granulosa and cumulus cells during folliculogenesis. Both Etv5 and Etv4 mRNAs are also detected in cumulus–oocyte complexes (COCs) and denuded oocytes. Notably, Etv4 is highly expressed in the cumulus cells of ovulated COCs at 16-h post-human chorionic gonadotropin. Cyclooxygenase-2 (PTGS2), a rate-limiting enzyme for prostaglandin synthesis, is critical for oocyte maturation and ovulation. Since several putative Ets-binding sites are present in the PTGS2 promoter, we examined whether Etv5 influences Ptgs2 transcriptional activity. Indeed, we found that addition of Etv5 increases the transcriptional activity of the 3.2-kb mouse Ptgs2 promoter by 2.5-fold in luciferase reporter assays. Collectively, the results show that Etv4 and Etv5 are expressed in granulosa and cumulus cells during folliculogenesis and ovulation, suggesting that they influence cellular events in the ovary by regulating downstream genes such as Ptgs2.