A fitter type generally has higher chances of disseminating their

A fitter type generally has higher chances of disseminating their copies to other individuals. The fixation Probability of a single mutant type introduced in a population of wild-type individuals quantifies how likely the Mutant type spreads. How much the excess fitness of the mutant type increases Mocetinostat solubility dmso its fixation probability, namely, the selection pressure, is important in assessing the impact

of the introduced mutant. Previous studies mostly based Oil undirected and unweighted contact networks of individuals showed that the selection pressure depends on the Structure of networks and the rule Of reproduction. Real networks underlying ecological and social interactions are usually directed or weighted. Here we examine how the selection pressure is modulated by directionality of interactions Under Nepicastat datasheet several update rules. Our conclusions are twofold. First, directionality, discounts the selection pressure for different networks and update rules. Second, given a network, the update rules in which death events precede reproduction events significantly decrease the selection pressure than the other rules. (C) 2008 Elsevier Ltd. All rights reserved.”
“Administration of human follicle-stimulating hormone (hFSH) to female rats during diestrus phase attenuates the spontaneous luteinizing hormone (LH) surge in proestrous afternoon. The

inhibition of LH secretion is associated with a decreased pituitary LH content in intact, but not in ovariectomized rats injected with 25 mu g estradiol benzoate (EB). GPX6 This suggests that the mechanism of action of the putative

non-steroidal ovarian bioactive FSH-dependent gonadodotropin surge attenuating factor (GnSAF) might, in addition, involve a reduction in LH synthesis. The present experiments studied, in proestrous pituitaries, the effects of different doses of hFSH, with or without EB on: (i) basal and GnRH-stimulated LH release and GnRH self-priming, (ii) LH beta mRNA values, and (iii) LH content. Results showed that bioactive GnSAF reduced mainly GnRH self-priming, but also GnRH-stimulated LH secretion and pituitary LH content in a dose-dependent manner. GnSAF had no effect on basal LH secretion or pituitary LH beta mRNA values. EB increased pituitary sensitivity to GnRH in controls, and overcame the inhibitory effects of GnSAF after low doses of hFSH but not after 10 IU of hFSH. In contrast with the sensitizing action of EB on LH secretion, EB had no effect on pituitary LH beta mRNA content or LH protein. It is concluded that the putative GnSAF blunted the LH surge by reducing LH synthesis at post-transcriptional level and antagonizing the GnRH-dependent LH secretion and the sensitizing effect of estradiol to GnRH. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

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