Antigonadotropic and Antisteroidogenic Actions of Peroxide in Rat Granulosa Cells*

Abstract

Reactive oxygen species are produced in the ovary. In luteal cells, peroxide abruptly inhibits LH-sensitive cAMP and progesterone production, and may serve a role as a mediator of luteolysis by such mechanisms. The objective of the present studies was to evaluate the acute actions of peroxide in rat granulosa cells. Peroxide at concentrations in the low micromolar range produced a marked and dose-dependent inhibition of FSH-sensitive cAMP accumulation and progesterone production, and depleted cell levels of ATP within 1 min. Longer treatment with peroxide (60 min) caused complete abrogation of the actions of FSH. Peroxide-induced depletion of ATP was prevented by 3-aminobenzamide, an inhibitor of DNA repair, but maintenance of cell levels of ATP did not prevent the anti-FSH effects of peroxide. Peroxide also abrogated cAMP accumulation and progesterone production in response to LH in granulosa cells. Unlike that seen with LH, inhibition of FSH-sensitive cyclic AMP accumulation by peroxide was partially reversed with isobutylmethyl xanthine, an inhibitor of cyclic AMP phosphodiesterase. Although peroxide inhibited cAMP accumulation in response to cholera toxin, it did not inhibit this same response to forskolin, which indicates that peroxide may interfere with G-protein-dependent activation of adenylate cyclase. Peroxide inhibited steroidogenesis in response to cholera toxin, forskolin, and 8-bromo-cAMP. The marked inhibitory actions of peroxide on gonadotropic hormone action and steroidogenesis in granulosa cells raise the possibility that peroxide may mediate events associated with loss of follicular function.

Effect of Selenium Nanoparticles on Anti-Oxidative Level, Egg Production and Quality and Blood Parameter of Laying Hens Exposed to Deoxynivalenol

“…In this research, the levels of these enzymes were significantly (P<0.05) inhibited by DON compared with the control, indicating that DON could induce oxidative stress in laying hens. This result is consistent with the previous research described above, and studies have also found that oxidative stress affects the female reproductive system by inhibiting follicle cell growth [26,27] or by even damaging ovarian and uterine cells. This is the probable explanation for why the DON group exhibited a lower egg production rate (71.15%) compared with the other groups.…”

“…The selenium nanoparticle (SeNP), which is one form of elemental selenium (Se0), has lower toxicity and better absorption and it is most effective when provided to broiler chicken under oxidative stress with the same dose but different sources of Se (organic, inorganic and nano-Se) [28]. According to some studies, the size of SeNPs synthesized by microorganisms has mostly been between 20 and 300 nm [20,26,27], and the diameter of the SeNPs in this research was 50 to 110 nm, which is consistent with previous research.…”

Changes in the glucose-6-phosphate dehydrogenase activity in granulosa cells during follicular atresia in ewes

“…Therefore, the survival of follicles subjected to gonadotropin stimulation is related to an increase in the expression of antioxidant enzymes (Tilly & Tilly 1995), while treatment with antioxidants blocks granulosa cell apoptosis in cultured follicles (Tilly 1996). Among the most noteworthy deleterious effects of ROS on follicular cells is the inhibition of induction of steroidogenesis by gonadotropic hormone with the loss of follicular function (Margolin et al 1990). …”

H2O2 at physiological concentrations modulates Leydig cell function inducing oxidative stress and apoptosis

“…2 It is shown to have marked antigonadotropic activity in luteal and granulosa cells and blocks basal and stimulated progesterone production. 3,4 In the thyroid gland, H 2 O 2 plays an important role in the thyroid hormone synthesis. 5 As a reactive oxygen species, it is generated from nearly all sources of oxidative cycle and has the ability to diffuse in and out of cells and tissues.…”