Granulosa cells (GCs) are somatic cells essential for establishing and maintaining bi-directional communication with the oocytes. This connection has a profound importance for the delivery of energy substrates, structural components and ions to the maturing oocyte through gap junctions. Cumulus cells, group of closely associated GCs, surround the oocyte and can diminished the effect of harmful environmental insults. Both GCs and oocytes prefer different energy substrates in their cellular metabolism: GCs are more glycolytic, whereas oocytes rely more on oxidative phosphorylation pathway. The interconnection of these cells is emphasized by the fact that GCs supply oocytes with intermediates produced in glycolysis. The number of GCs surrounding the oocyte and their age affect the energy status of oocytes. This review summarises available studies collaboration of cellular types in the ovarian follicle from the point of view of energy metabolism, signaling and protection of toxic insults. A deeper knowledge of the underlying mechanisms is crucial for better methods to prevent and treat infertility and to improve the technology of in vitro fertilization.

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Glucagon-like peptide-1 (GLP-1) is an incretin known for proliferative and antiapoptotic effects on various tissues. Exenatide and Liraglutide are GLP-1 analogues used in clinical practice as antidiabetic drugs. Since GLP-1 and its analogues exert significant effect on liver metabolism and since changes in intermediary metabolism play an important role in the process of liver regeneration, we decided to determine the effect of Exenatide and Liraglutide on the early phase of liver regeneration and selected metabolic parameters in a model of 2/3 partial hepatectomy (PHx) in rats. Animals were submitted either to PHx or laparotomy and received 3 doses of either GLP-1 analogues (Exenatide – 42 μg/kg b.w., Liraglutide – 0.75 mg/kg b.w.) or saline intraperitoneally. We analyzed body and liver weight, liver bromodeoxyuridine incorporation, liver content of DNA, triacylglycerols and cholesterol and biochemical serum parameters. Bromodeoxyuridine labeling was significantly lower in hepatectomized rats receiving either type of GLP-1 analogues when compared to hepatectomized controls. This effect was more pronounced in the Liraglutide group compared to Exenatide (p<0.001). In addition, liver DNA content was lower in hepatectomized rats receiving Liraglutide than in hepatectomized control rats (p<0.001). In conclusion, GLP-1 analogues Exenatide and Liraglutide significantly inhibited an early phase of liver regeneration after PHx in rats. This inhibitory effect was more pronounced in rats receiving Liraglutide.

Non-alcoholic fatty liver disease and its complications are frequent causes of liver-related morbidity and mortality. Incretin glucagon-like peptide-1 (GLP-1) affects liver functions and metabolism. Although GLP-1 analogues are widely used in clinical practice, information regarding their potential toxic effect on hepatocytes in vitro is missing. Therefore, we evaluated the effect of GLP-1 analogue liraglutide on activity of caspases 3/7, cell viability and oxidative stress in primary cultures of hepatocytes. Primary cultures isolated from male Wistar rats fed a standard (ST1-group, 10% energy from fat) or a high-fat diet (HF-group, 71% fat) for 10 weeks were incubated with liraglutide (0.1-1000 nmol/l) for 24 h. Activities of caspases 3/7 and cellular dehydrogenases (WST-1), lactate dehydrogenase (LDH) leakage and oxidative stress (malondialdehyde concentration and DCFDA assay) were evaluated. HF-groups vs. ST1-groups showed higher caspases activity, LDH leakage and MDA production (p < 0.001) and lower cellular dehydrogenases activity (p < 0.01). Liraglutide induced a dose-dependent decrease of caspases activity in both groups, reduction of oxidative stress in HFanimals and exerted no negative effects on other parameters. In conclusion, GLP-1 analogue liraglutide decreased activity of caspases 3/7, reduced ROS production and didn't exhibit negative effects on cell viability and oxidative stress in primary cultures of hepatocytes isolated from lean and steatotic livers.

Bisphenol S (BPS), the main replacement for bisphenol A (BPA), is thought to be toxic, but limited information is available on the effects of Bisphenol S on ovarian follicles. In our study, we demonstrated the presence of Bisphenol S in the follicular fluid of women at a concentration of 22.4 nM. The effect of such concentrations of Bisphenol S on oocyte maturation and subsequent embryo development is still unknown. Therefore, we focused on the effect of Bisphenol S on in vitro oocyte maturation, fertilization, and embryo development. As a model, we used porcine oocytes, which show many physiological similarities to human oocytes. Oocytes were exposed to Bisphenol S concentrations similar to those detected in female patients in the ART clinic. We found a decreased ability of oocytes to successfully complete meiotic maturation. Mature oocytes showed an increased frequency of meiotic spindle abnormalities and chromosome misalignment. Alarming associations of oocyte Bisphenol S exposure with the occurrence of aneuploidy and changes in the distribution of mitochondria and mitochondrial proteins were demonstrated for the first time. However, the number and quality of blastocysts derived from oocytes that successfully completed meiotic maturation under the influence of Bisphenol S was not affected.

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