Effect of Vitamin D3 on Chemerin and Adiponectin Levels in Uterus of Polycystic Ovary Syndrome Rats.

BACKGROUND: Polycystic ovary syndrome (PCOS) is an endocrine disorder with disrupted uterus structure and function. A positive effect of vitamin D3 (VD3) in female reproduction was observed. Chemerin (RARRES2) and adiponectin (ADIPOQ) are the main adipokines whose levels are altered in PCOS patients. Therefore, the aim of this study was to investigate the impact of VD3 supplementation on RARRES2 and ADIPOQ levels in the uterus of PCOS rats. METHODS: We analyzed the plasma levels and uterine transcript and protein expression of RARRES2 and ADIPOQ and their receptors (CCRL2, CMKLR1, GPR1, and ADIPOR1 and ADIPOR2, respectively) in rats with letrozole-induced PCOS. RESULTS: In control animals, VD3 did not change plasma levels of both adipokines, while in PCOS rats supplemented with VD3, they returned to control levels. The expression of RARRES2 and all investigated receptors increased in the uterus of VD3-treated rats; however, the levels of Rarres2 and Gpr1 genes remained unchanged. VD3 supplementation decreased RARRES2, CMKLR1, and GPR1 but increased CCRL2 level to the control value. In the uterus of VD3-treated rats, the transcript and protein levels of ADIPOQ and both receptors ADIPOR1 increased. At the same time, VD3 supplementation induced an increase in Adipoq, Adipor1, and Adipor2 gene expression and restored protein levels to control level values. CONCLUSIONS: our findings indicate a new mechanism of VD3 action in the uterine physiology of PCOS rats.

Levels of spexin and its receptors GALR2 and GALR3 in the hypothalamus and ovary of letrozole-induced polycystic ovary syndrome in rats.

Spexin (SPX) is a newly identified neuropeptide, a natural ligand for the galanin receptors (GALR) 2/3, which is involved in maintaining physiological functions including female reproduction. One of the most common endocrine disorder in reproductive system is polycystic ovary syndrome (PCOS), however the role of SPX in PCOS is still unknown. The objective of this study was to determine the expression of mRNA and peptide levels of SPX and its receptors GALR2/3 in the hypothalamus and ovary (by real time PCR and Western blot) as well as plasma levels of SPX (ELISA) in letrozole - induced PCOS rats. We observed that SPX plasma level does not change in PCOS rats. In the hypothalamus transcript level of Spx and Galr3 were significantly higher in PCOS rats compared to the control, while mRNA of Galr2 and protein expression of GALR2/3 were lower. Moreover, expression of Spx and Galr2/3 mRNA as well as GALR2/3 peptide production were lower in the ovary of PCOS rats. In summary, while our results did not show differences in plasma SPX levels, we observed tissue-dependent significant differences in the SPX/GALR2/3 levels between PCOS and control rats, what indicates possible new mechanisms of PCOS neuroendocrinology.

Plasma level and expression of visfatin in the porcine hypothalamus during the estrous cycle and early pregnancy.

Visfatin appears to be an energy sensor involved in the regulation of female fertility, which creates a hormonal link integrating the control of energy homeostasis and reproduction. This study evaluates the expression levels of visfatin gene and protein in selected areas of the porcine hypothalamus responsible for gonadotropin-releasing hormone synthesis: the mediobasal hypothalamus (MBH) and preoptic area (POA), and visfatin concentrations in the blood plasma. The tissue samples were harvested from gilts on days 2-3, 10-12, 14-16, and 17-19 of the estrous cycle, and on days 10-11, 12-13, 15-16, 27-28 of pregnancy. Visfatin was localized in the cytoplasm and nucleus of cells creating both studied hypothalamic structures. The study demonstrated that visfatin gene and protein expression in MBH and POA depends on hormonal status related to the phase of the estrous cycle or early pregnancy. Blood plasma concentrations of visfatin during the estrous cycle were higher on days 2-3 in relation to other studied phases of the cycle, while during early pregnancy, the highest visfatin contents were observed on days 12-13. This study demonstrated visfatin expression in the porcine hypothalamus and its dependence on the hormonal milieu related to the estrous cycle and early pregnancy.

Energy sensors and reproductive hypothalamo-pituitary ovarian axis (HPO) in female mammals: Role of mTOR (mammalian target of rapamycin), AMPK (AMP-activated protein kinase) and SIRT1 (Sirtuin 1).

In female, energy metabolism influences reproductive function by modulating the Hypothalamic Pituitary Ovarian axis including the hypothalamic GnRH neuronal network, the pituitary gonadotropin secretion and the ovarian follicle growth and steroidogenesis. Several hormones and neuropeptides or metabolites are important signals between energy balance and reproduction. These energy sensors mediate their action on reproductive cells through specific kinases or signaling pathways. This review focuses on the role of three main enzymes-specifically, mTOR, AMPK, and SIRT1 at the hypothalamic pituitary and ovarian axis in normal female fertility and then we discuss their possible involvement in some women reproductive disorders known to be associated with metabolic complications, such as polycystic ovary syndrome (PCOS) and premature ovarian failure (POF).

Levels of the neuropeptide phoenixin-14 and its receptor GRP173 in the hypothalamus, ovary and periovarian adipose tissue in rat model of polycystic ovary syndrome.

Phoenixin (PNX) is a newly discovered peptide produced by proteolytic cleavage of a small integral membrane protein 20 (Smim20), which acts as an important regulator of energy homeostasis and reproduction. Since dysfunction of reproduction is characteristic in polycystic ovarian syndrome (PCOS), the role of PNX in pathogenesis of PCOS needs further investigation. The objective of this study was to determine expression of Smim20, PNX-14 and its receptor GRP173 in the hypothalamus, ovary and periovarian adipose tissue (PAT) of letrozole induced PCOS rats. Phosphorylation of extracellular signal-regulated kinase (ERK1/2), protein kinases A (PKA) and B (Akt) were also estimated. We observed that PCOS rats had high weight gain and a number of ovarian cyst, high levels of testosterone, luteinizing hormone and PNX-14, while low estradiol. Smim20 mRNA expression was higher in the ovary and PAT, while PNX-14 peptide production was higher only in the ovary of PCOS rat. Moreover, in PCOS rats Gpr173 level was lower in PAT but at the protein level increased only in the ovary. Depending on the tissues, kinases phosphorylation were significantly differ in PCOS rats. Our results showed higher levels of PNX-14 in PCOS rats and indicated some novel findings regarding the mechanisms of PCOS pathophysiology.

Induction of cytochrome P450 1A1 in MCF-7 human breast cancer cells by 4-chlorobiphenyl (PCB3) and the effects of its hydroxylated metabolites on cellular apoptosis.

Several studies suggest an involvement of PCBs in breast cancer formation, but the results are ambiguous and the mechanisms not clear. We propose that local activation of cytochrome P450 enzymes, CYP1A1 and CYP1B1 by PCB3, may generate active metabolites which affect apoptosis and thereby promote mammary carcinogenesis. To test this hypothesis MCF-7 human breast cancer cells were exposed to 300 nM PCB3 and its hydroxylated metabolites, 4OH-PCB and 3,4diOH-PCB3. The enzyme activity for CYP1A1 was assayed using the EROD assay, and CYP1A1 and CYP1B1 protein expression by western blotting. PCB3 increased CYP1A1 activity (~1.5fold) and protein levels within 6h after exposure. No effect on CYP1B1 protein expression was observed. The effects of PCB3 and both its metabolites on staurosporine-induced apoptosis were determined by measuring DNA fragmentation using ELISA and TUNEL assays, and by measuring caspase-8 and caspase-9 activity. We found that PCB3 and both of its hydroxylated metabolites had no effect on caspase-8 and caspase-9 activity when cells were grown in medium deprived of estrogen, but reduced caspase-9 activity when cells were grown in medium supplemented with serum containing estradiol. Interestingly, a decrease of DNA fragmentation was observed upon treatment with 3,4diOH-PCB3 in both culture conditions, suggesting that 3,4diOH-PCB3 affects a caspase-independent pathway of cell death. In summary, interactions of PCB3 and its metabolites with estradiol by yet unknown mechanisms inhibit caspase 9-related apoptosis and additional, other death pathways are affected by the catechol metabolite 3,4diOH-PCB3. These anti-apoptotic effects and the change in metabolic activity may contribute to the carcinogenic effect of PCBs.