Effects of chronic exposure to cold stress on ovarian functions in prepubertal rats.

Ovarian functions are modulated by the hypothalamus-pituitary-ovary axis and neural signals. Stress modifies the activity of the sympathetic nervous system. In adult female rats, cold stress results in higher noradrenergic and steroidogenic activity of the ovary, anovulation and the presence of ovarian cysts; however, it is unknown whether this response occurs in prepubertal rats. The purpose of this study was to analyse the effects of cold stress initiated in the prepubertal stage of female rats on ovarian function. Female rats 24 days old were exposed to three, five or eight weeks of cold stress. Autopsies were performed at the end of each stress period. The parameters analysed were the number of ova shed by ovulating animals; the number of ovulating animals; the serum concentrations of progesterone, testosterone, and oestradiol; and the ovarian concentrations of norepinephrine and 3-methoxy-4-hydroxyphenyl-glycol. Our results show that chronic cold stress applied to prepubertal rats did not modify the number of ovulating animals, the total number of ova shed, or progesterone and testosterone concentrations in any of the periods analysed. Oestradiol concentration was lower in the animals exposed to five or eight weeks of stress. The ovarian norepinephrine concentration was higher in the animals exposed to three weeks of stress and was lower at eight weeks of stress. No changes in ovarian morphology were observed. Our data suggest that the changes in noradrenergic activity resulting from chronic cold stress experienced in the prepubertal stage do not modify ovarian architecture or affect the ovulatory response in adulthood.

Role of the superior ovarian nerve in the regulation of follicular development and steroidogenesis in the morning of diestrus 1.

PURPOSE: Little is known about the role of the superior ovarian nerve (SON) in follicular development during the estrus cycle. The aim of the present study was to analyze the role of neural signals arriving through the SON at the ovaries in the regulation of follicular development and ovarian steroid secretion in diestrus 1 of cyclic rats. METHODS: Cyclic rats were subjected to left, right, or bilateral SON sectioning or to unilateral or bilateral laparotomy at diestrus 1 at 11:00 h. Animals were sacrificed 24 h after surgery. RESULTS: Compared to laparotomized animals, unilateral SON sectioning decreased the number of preovulatory follicles, while bilateral SON sectioning resulted in a decreased number of atretic preantral follicles. An important observation was the presence of invaginations in the follicular wall of large antral and preovulatory follicles in animals with denervation. Furthermore, left SON sectioning increased progesterone levels but decreased testosterone levels, which are effects that were not observed in animals that were subjected to right denervation. CONCLUSIONS: At 11:00 h of diestrus 1, the SON was found to stimulate follicle development, possibly via neural signals, such as noradrenaline and/or vasoactive intestinal peptide, and this stimulation induced the formation of follicle-stimulating hormone receptors. The role of the SON in the regulation of ovarian steroid secretion is asymmetric: the left SON inhibits the regulation of progesterone and stimulates testosterone secretion, and the right nerve does not participate in these processes.

Endocrine disruptor effect of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) on porcine ovarian cell steroidogenesis.

Previous studies with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) indicate that they act as endocrine disruptors, in addition to inducing alterations and damaging reproductive health; however, the biological mechanisms by which these disorders are produced are not yet understood. The aim of this study was to analyze the effect of PFOS and PFOA on in vitro steroidogenic secretion in porcine theca and granulosa cells, with or without gonadotropic stimulation. Granulosa and theca cells were isolated and cultured. Cell nature was performed by immunocytochemistry. PFOS and PFOA effect on steroid secretion was analyzed by chemiluminescence. In the present study, alterations in steroidogenic secretion were found when administering PFOS (0.12, 1.2, 12, 120 or 240µM) or PFOA (0.012, 0.12, 1.2, 12 or 24µM) to theca and granulosa cells. When theca and granulosa cells were stimulated with 500ng/mL LH or 500ng/mL FHS, respectively and immediately followed with 1.2µM of PFOS or PFOA, the perfluorinated compounds inhibited the secretion of steroid hormones in both stimulated cell types. The results indicate that PFOS and PFOA act on steroidogenic ovarian cells as endocrine disruptors, which could affect the dependent functions of sexual steroids.