The effects of bisphenol A on sex hormone levels of F0 female rats and F1 male rats during weaning period

The effects of bisphenol A (BPA) were examined on sex hormones of F1 generation male rats during weaning period. Female rats were exposed to BPA from day 0 after pregnancy to the weaning period at doses of 50, 100, or 200 mg kg^?1. The sex hormone levels of F1 generation male rats were determined. This study shows that F0 generation female rats fed with 200 mg kg^?1 BPA had a significantly higher serum prolactin (PRL) levels at the end of weaning. Significantly higher levels of serum estradiol (E₂) were also found in female rats fed 100 or 200 mg kg^?1 BPA. Serum levels of E₂ in F1 male generation rats were higher in treatment groups compared to control groups while serum testosterone (T) levels were lower. Follicle stimulating hormone (FSH) in F1 generation rats fed 200 mg kg^?1 was markedly decreased. The relative testicular weights were significantly less in 100 and 200 mg kg^?1 BPA groups. BPA was found to alter the sex hormone levels in F1 male rats during weaning period and thus disrupted endocrine functions.     

EEDs对鱼类性激素合成途径干扰作用研究进展

环境内分泌干扰物(environmental endocrine disruptors,EEDs)是一类可以改变生物体内激素的合成、释放、运输、代谢、结合、作用或清除等一系列生物过程的外源物质。性激素的生物合成需要一系列酶的参与,体内和体外研究表明,性激素合成途径中的类固醇生成酶是EEDs通过非性激素受体介导途径发挥内分泌扰乱作用的重要靶点,性激素合成途径的扰乱可能导致生物体生殖系统受损。本文综述了EEDs对鱼类性激素合成底物和类固醇生成酶的影响、信号转导机制及其生殖危害;并对性激素合成途径中促性腺激素调控机理、多种转录因子间的相互作用、不同物种间类固醇生成酶的差异以及各内分泌轴线的相互作用研究进行了展望,以期为EEDs通过非性激素受体介导途径发挥内分泌干扰效应的机制研究提供思路。     

环境内分泌干扰物对鱼类性别决定的影响研究进展

水体中的环境内分泌干扰物能够影响鱼类性别决定过程,对鱼类产生明显的雌、雄性化效应.为深入研究环境内分泌干扰物对鱼类性别决定的影响及其机制,论文介绍了鱼类性别决定基因SRY和DMY基因在鱼类性别决定中的作用,以及Sox、DMRT、CYP和Vasa、Dax1、Foxl2等鱼类性别决定相关基因对鱼类性别决定的调控作用,综述了各类环境内分泌干扰物引起的鱼类雌、雄性化效应的最新研究进展,在此基础上探讨了环境内分泌干扰物影响鱼类性别决定的作用机制,并展望了该领域今后的重点研究方向.     

A synomone imparting distinct sex pheromone communication channels for Choristoneura rosaceana (Harris) and Pandemis limitata (Robinson) (Lepidoptera: Tortricidae)

Summary. Male obliquebanded leafrollers, Choristoneura rosaceana (Harris), were induced to respond to a pheromone source tainted with a behavioural antagonist, Z9-tetradecenyl acetate, when a source releasing the antagonist was placed 10 cm upwind of the tainted source in a wind tunnel. However, placement of the antagonist upwind of an attractive pheromone source did not interrupt pheromone-mediated responses. Placement of a source releasing Z9-tetradecenyl acetate, a minor pheromone component of the sympatric species, the threelined leafroller, Pandemis limitata (Robinson), upwind of a calling P. limitata female, reduced conspecific male pheromone-mediated response but resulted in upwind flight by male C. rosaceana and contact with heterospecific females. Male P. limitata locked on and flew upwind to but did not contact heterospecific females when a source releasing Z9-tetradecenyl acetate was positioned upwind of a calling C. rosaceana female. In the field, adaptation or habituation to Z9-tetradecenyl acetate caused by atmospheric treatment with this compound apparently resulted in reciprocal heterospecific pheromone responses. More C. rosaceana males were captured in traps baited with their pheromone and the behavioural antagonist in small field plots treated atmospherically with Z9-tetradecenyl acetate than in nontreated control plots. Fewer male P. limitata were captured in traps baited with their own pheromone, or with C. rosaceana pheromone tainted with Z9-tetradecenyl acetate in plots treated atmospherically with Z9-tetradecenyl acetate than in nontreated control plots. We argue that Z9-tetradecenyl acetate is an important synomone which assists in partitioning the sexual chemical communication channels of C. rosaceana and P. limitata. Received 9 February 1999; accepted 22 March 1999.     

Birth sex ratios in toque macaques and other mammals: integrating the effects of maternal condition and competition

Mammalian life histories suggest that maternal body condition and social dominance (a measure of resource-holding potential) influence the physical and social development of offspring, and thereby their reproductive success. Predictably, a mother should produce that sex of offspring which contributes most to her fitness (as measured by the number of her grandchildren) and that she is best able to raise within the constraints imposed by her condition, social rank, and environment. Such combined effects were investigated by monitoring variations in body condition (weight) and behavior of female toque macaques, Macaca sinica of Sri Lanka, in a changing forest environment over 18 years. Maternal rank, by itself, had no influence on offspring sex, but did affect maternal body condition. The combined effects of rank and condition indicated the following: mothers in robust condition bore more sons, whereas those in moderate condition bore more daughters, but both effects were expressed most strongly among mothers of high rank. Where the consequences of low rank were felt most acutely, as shown by poor condition, mothers underproduced daughters. Environmental quality directly influenced rank and condition interactions, and thus sex ratios. These relationships, and data from other mammals suggest an empirically and theoretically consistent pattern of sex allocation in mammals. New predictions integrate effects, proposed by Trivers and Willard, that are rooted in male mate competition, which is universal among polygynous mammals, with those of local resource competition (and/or female reproductive competition), which are not universal and differ in intensity between the socioecologies and local environments of different species. Received: 30 May 1998 / Accepted after revision: 29 August 1998     

BSA体系中2,4-D和阿特拉津对性激素的干扰机理

在2,4-D和阿特拉津以及天然性激素(雌二醇、睾酮)中加入牛血清白蛋白(BSA),通过紫外吸收峰的变化、温度与体系荧光强度的关系、以及计算扩散碰撞猝灭常数Kq等方法确定2,4-D和阿特拉津均可以发生类似天然性激素和BSA间的基态络合.并通过双倒数公式计算出各自二元体系的结合常数.2,4-D、阿特拉津、雌二醇、睾酮与BSA的结合常数(K)均在104数量级,可以认为2,4-D和阿特拉津具有与天然性激素相近的对BSA结合能力,并可通过竞争占据结合位点的方式干扰正常性激素与BSA的结合.     

多氯联苯(PCBs)胁迫下鲫鱼肝脏EROD酶活性与血清性激素含量的相关性研究

以鲫鱼(Carassius auratus)为试验鱼类,研究其暴露于不同浓度的PCBs(多氯联苯)后鱼肝组织中EROD酶活性和血清性激素含量的动态变化,探讨了2者间的相关性。结果表明,鲫鱼在PCBs中暴露后,其肝脏组织中EROD酶被诱导,酶活性随PCBs浓度增大而增强,呈明显的剂量-效应关系;EROD酶活性随暴露时间延长而上升,10 d后达平衡;鲫鱼血清中睾酮含量随PCBs浓度增大和暴露时间延长呈下降趋势,但雌二醇含量则显著上升,表明PCBs对鱼类具有环境雌激素效应;在一定浓度范围内,EROD酶活性与血清睾酮含量呈负相关,与血清雌二醇含量呈正相关。因此可用鱼肝EROD酶和血清性激素含量的协同变化作为污染生物标志物来评价PCBs的早期污染生态效应。     

棉铃虫灾害的长期性及性信息素的减灾控害作用

简要分析了我国棉铃虫灾害的长期性,并较全面地介绍了性信息素在减灾控害中的作用。这些作用可分为：帮助识别对象害虫、监测种群状态、迅速普及虫情信息、直接诱杀雄虫以及提前1周开展减灾行动等。直接诱杀雄虫后,引起雌雄比上升,雌蛾产卵量下降,孵化率降低,幼虫及为害量减少,其中幼虫量一般减少20％－50％。根据在新疆、山东等地的试用经验,作者在首次指出性信息帮助识别害虫和迅速普及虫情信息对减灾的关键作用,并讨论了性信息素的干扰交配和诱杀雌虫的可能作用,以及使用性信息素与农业可持续发展的关系。     

Sex Structure of Scotch Pine Populations in the Dry Steppe

it has been determined that the sex structure of the population is of great importance for pine adaptation to extreme environmental conditions. As environmental conditions deteriorate, differentiation of populations with respect to sex becomes more apparent, the proportion of trees of mixed type decreases, and the number of male trees increases. A tendency toward correlation between tree habitus, needle and shoot sizes, and the sex structure of population is noted. The prevalence of male trees in populations exposed to increasing stress reflects the rearrangement of such populations aimed at the more efficient use of natural resources.     

Women and children last: An essay on sex discrimination in disasters

In general, little attention has been given to differential survival between the sexes in disasters. Consideration of physiological differences between males and females would suggest that, all things being equal, morbidity and mortality after disaster, particularly where food shortage is involved, should indicate an excess male mortality. Such statistics as exist in disasters, as in chronic underdevelopment, show that it is females and especially girl children who are at highest risk. The basis of this lies in sex discrimination which is implicit in most social systems.