Reactive oxygen species are indispensable in ovulation

Ovulation is stimulated by the preovulatory surge of the pituitary luteinizing hormone (LH). Because the ovulatory response is commonly identified with inflammation, we explored the involvement of reactive oxygen species (ROS) in this process. Our experiments show that administration of broad-range scavengers of oxidative species into the ovarian bursa of mice, hormonally induced to ovulate, significantly reduced the rate of ovulation. LH-induced cumulus mucification/expansion, a necessary requirement for ovulation, was prevented by antioxidants both in vivo and in an ex vivo system of isolated intact ovarian follicles. Along this line, H2O2 fully mimicked the effect of LH, bringing about an extensive mucification/expansion of the follicle-enclosed cumulus–oocyte complexes. Impaired progesterone production was observed in isolated follicles incubated with LH in the presence of the antioxidant agents. Furthermore, LH-stimulated up-regulation of genes, the expression of which is crucial for ovulation, was substantially attenuated upon ROS ablation. This system was also used for demonstrating the role of ROS in phosphorylation and activation of the EGF receptor as well as its downstream effector, p42/44 MAPK. Together, our results provide evidence that ovarian production of ROS is an essential preovulatory signaling event, most probably transiently triggered by LH

Carbon leakage revisited: unilateral climate policy with directed technical change

Climate Policy, Carbon Leakage, Directed Technical Change, International Trade, F18, O33, Q54, Q55,

Seminal plasma regulates ovarian progesterone production, leukocyte recruitment and follicular cell responses in the pig

Copyright © 2006 Society for Reproduction and FertilitySeminal plasma (SP) acts to influence the uterine endometrium after mating, activating synthesis of embryotrophic cytokines and inflammatory changes that condition the tract for embryo implantation and establishing pregnancy. The objective of this study was to investigate in pigs whether the ovary might also be responsive to SP exposure. Prepubertal gilts were synchronised with exogenous gonadotrophins and received transcervical treatment with pooled boar SP or PBS; then the ovarian tissue was recovered at 34 h (preovulation) and on days 5 and 9 after treatment. The ovarian response was assessed by measuring ovulation rate, number and size of corpora lutea, ovarian leukocyte populations, progesterone production in vivo, as well as responses of retrieved granulosa cells cultured in vitro. In SP-treated gilts, leukocyte recruitment into the ovarian tissues was increased fourfold at 34 h, with macrophages comprising the most abundant cell lineage. There was no effect of SP on the number of oocytes ovulated; however, the weight of corpora lutea was increased in SP-treated gilts. SP also induced an increase in plasma progesterone content seen from day 5 to at least day 9 after treatment. In addition, granulosa cells and thecal tissue retrieved from preovulatory follicles of SP-treated gilts were more responsive in vitro to growth factor- and gonadotrophin-stimulated cell proliferation and progesterone synthesis. These results suggest that uterine exposure to SP influences immune cell trafficking in the ovary and enhances steroidogenesis in early pregnancy. The effects of SP on ovarian function potentially contribute to reproductive success in the pig.S O’Leary, M J Jasper, S A Robertson and D T Armstron

EXTREMELY STRONG CARBON-MONOXIDE EMISSION FROM THE CLOVERLEAF QUASAR AT A REDSHIFT OF 2.5

GALAXIES at high redshift are very faint and difficult to study at optical and near-infrared wavelengths, but detection of far-infrared emission(1) and molecular gas(2,3) in a galaxy at redshift z approximate to 2.3 has suggested that their early evolution may be investigated by these means instead. The host galaxies of quasars are promising candidates for these observations, particularly as quasars might be triggered by interactions and mergers between galaxies(4,5) which result in dust- and gas-rich systems. The Cloverleaf, a gravitationally lensed quasar, has far-infrared/submillimetre emission indicating a substantial dust content(6), and therefore potentially a large amount of gas. Here we report the detection of carbon monoxide emission from the Cloverleaf, which we interpret as indicating a mass of molecular gas that is comparable to the total dynamical mass of the host galaxy, and which is consistent with the total baryonic content of a present-day luminous galaxy. This suggests that, although some processing of gas through stars has taken place in the Cloverleaf at a lookback time of 85% of the current age of the Universe, much of the future stellar content has yet to be formed