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The present study investigated the role of the N, N{′ }-dimethylbiguanide metformin (50 mg/100 g body weight in 0.05 ml water, given orally with a canulla) in the prevention of endocrine and immune disorders provoked by the hyperandrogenization with dehydroepiandrosterone (DHEA) in prepuberal BALB/c mice. The treatment with DHEA (6 mg/100 g body weight in 0.1 ml oil) for 20 consecutive days, recreates a mouse model that resembles some aspects of the human polycystic ovary syndrome (PCOS). The treatment with DHEA did not modify either body mass index (BMI) or blood glucose levels, but did increase fasting insulin levels when compared with controls. Markers of ovarian function – serum estradiol (E), progesterone (P) and ovarian prostaglandin E (PGE) – were evaluated. The treatment with DHEA increased serum E and P levels while ovarian PGE diminished. When metformin was administered together with DHEA, serum insulin, E and P levels, and ovarian PGE values did not differ when compared with controls. Using flow cytometry assays we found that the treatment with DHEA diminished the percentage of the CD4 + T lymphocyte population and increased the percentage of the CD8 + T lymphocyte population from both ovarian tissue and retroperitoneal lymph nodes. However, when metformin was administered together with DHEA, the percentages of CD4 + and CD8 + T lymphocyte populations from both ovarian tissue and retroperitoneal lymph nodes were similar to those observed in controls. Finally, when DHEA was administered alone it increased the serum tumor necrosis factor-alpha (TNF-α ) levels when compared with controls; however, when metformin was administered together with DHEA, serum TNF-α levels were similar to controls. These results indicate that metformin is able, directly or indirectly, to avoid the endocrine and immune alterations produced when mice are hyperandrogenized with DHEA.

Obesity is a chronic disease that impairs female reproduction. When gestation is achieved, maternal obesity can cause offspring’s health complications. We intended to evaluate the effects of maternal pre-conceptional obesity on uterine contractile activity, embryo implantation and offspring development. Using cafeteria diet-induced obesity as an animal model, we found that maternal obesity delays embryo transport from the oviduct to the uterus and alters the intrauterine embryo positioning. Adrenergic receptor (AR) signaling is involved in embryo positioning, so all AR isoforms were screened in the pre-implantation uteri. We found that the β2AR is the dominant isoform in the rat uteri and that obesity causes its upregulation. Although β2AR activation is known to induce uterine relaxation, higher spontaneous contractile activity was detected in obese dams. Uteri from obese dams showed a higher sensitivity to salbutamol (a selective agonist of β2AR) than controls, consistent with the higher β2AR levels detected in those animals. Despite this, in obese dams, some embryos were still in the oviduct at the predicted time of initial embryo attachment, embryo implantation is successfully carried out since the total number of fetuses on gd 18.5 were similar between control and obese dams. These findings show that obesity is modifying the implantation window. Moreover, we found that maternal obesity resulted in macrosomia in the offspring, which is an important predictor of fetal programming of postnatal health. Hence, our results show that maternal obesity prior to pregnancy not only disturbs the implantation process, but also affects offspring development.