Matozzo Valerio, Gagné François, Marin Maria Gabriella, Ricciardi Francesco, Blaise Christian
Department of Biology, University of Padova, Via Ugo Bassi 58/B, Padova, Italy.
Environ Int. 2008 May;34(4):531-45. doi: 10.1016/j.envint.2007.09.008. Epub 2007 Oct 29.
Vitellogenins (Vg) are the major precursor of the egg-yolk proteins, vitellins (Vn), which provide energy reserves for embryonic development in oviparous organisms. In mature females, Vg are generally synthesised in response to endogenous estrogens, such as 17beta-estradiol (E2), released into the bloodstream and then stored in developing oocytes. In males, the Vg gene, although present, is normally silent. However, it may be activated by (xeno)-estrogens. These substances belong to a large and heterogeneous group of environmental contaminants capable of altering endocrine functions in organisms. For this reason, they are named endocrine disrupting chemicals (EDCs). Natural steroidal estrogens [E2, estrone (E1), estriol (E3)] and synthetic chemicals, such as pesticides, polychlorinated biphenyls (PCBs) and household products (surfactants) are estrogenic compounds widespread in aquatic ecosystems. The main sources of contamination mostly stem (or originate) from municipal and industrial effluents, agricultural practices, livestock wastes and sewage treatment plants (STP). Recently, Vg induction, mainly in males and immature females, has been proposed as a useful biomarker to assess estrogenic contamination in aquatic environments. Indeed, estrogenicity of individual chemicals and mixtures has extensively been evaluated, in both laboratory and field studies, albeit mostly in fish. In contrast, limited attention has centred on evaluating xenoestrogen effects in aquatic invertebrates, probably owing to limited knowledge of their endocrinology. This review focuses on a brief description of xenoestrogens and their occurrence in aquatic environments, and on Vg induction in aquatic invertebrates in response to both experimental and environmental exposure to estrogenic compounds. Results of recent field and laboratory studies are presented. In addition, new perspectives about the use of Vg induction as a biomarker of exposure to estrogenic compounds are also discussed.
卵黄蛋白原（Vg）是卵黄蛋白（Vn）的主要前体，卵黄蛋白为卵生生物的胚胎发育提供能量储备。在成熟雌性体内，Vg通常是响应内源性雌激素（如释放到血液中的17β-雌二醇（E2））而合成，然后储存在发育中的卵母细胞中。在雄性体内，Vg基因虽然存在，但通常处于沉默状态。然而，它可能会被（外源性）雌激素激活。这些物质属于一大类异质性环境污染物，能够改变生物体内的内分泌功能。因此，它们被称为内分泌干扰化学物质（EDC）。天然甾体雌激素[E2、雌酮（E1）、雌三醇（E3）]以及合成化学品，如农药、多氯联苯（PCB）和家用产品（表面活性剂），都是广泛存在于水生生态系统中的雌激素化合物。污染的主要来源大多源于城市和工业废水、农业活动、牲畜粪便以及污水处理厂（STP）。最近，主要在雄性和未成熟雌性体内诱导产生Vg，已被提议作为评估水生环境中雌激素污染的一种有用生物标志物。事实上，无论是在实验室研究还是野外研究中，都对单一化学品和混合物的雌激素活性进行了广泛评估，不过大多是针对鱼类。相比之下，对评估水生无脊椎动物中外源雌激素影响的关注有限，这可能是由于对其内分泌学的了解有限。本综述重点简要描述外源雌激素及其在水生环境中的存在情况，以及水生无脊椎动物在实验性和环境性接触雌激素化合物后Vg的诱导情况。文中呈现了近期野外和实验室研究的结果。此外，还讨论了将Vg诱导用作接触雌激素化合物生物标志物的新观点。
