Department of Marine Biogeochemistry and Toxicology, Netherlands Institute for Sea Research (NIOZ), PO Box 59, 1790 AB Den Burg, The Netherlands.
Environ Toxicol Pharmacol. 2002 Jan;11(1):49-65. doi: 10.1016/s1382-6689(01)00106-5.
Here we report a series of experiments on the development and occurrence of imposex in the common whelk, Buccinum undatum, under the influence of (chronic) exposure to butyltin compounds. The main objective of the experiments was to obtain more information about the effects of organotin compounds in the marine environment, which possibly relate to the reported decline of B. undatum in Dutch coastal waters. In these studies tributyltin (TBT) dose-dependently induced the development of male sexual organs in juvenile whelks. A TBT concentration >7 ng Sn/l induced imposex in juvenile whelks. Growth in TBT-exposed juvenile whelks was significantly reduced compared to the reference group at a nominal TBT dose ≥ 4 ng Sn/l in one of the exposure studies. After 5 years in the laboratory, egg-laying was only observed in reference aquaria. Thus, TBT might impair whelk reproduction through growth reduction. The results showed a sensitivity towards imposex development in different life-stages. Juveniles were the most sensitive, adolescent females also responded, but adult females did not respond to TBT exposure, although they dose-dependently increased their organotin (OT) body-burden when exposed. Environmental TBT during only the in ovo stage, did not result in an increased masculinisation compared to non-exposed developing whelks. Histological studies showed no sterilisation due to mechanical blockage of the (adult) female genital opening by sperm-duct tissue. Gonadal development in 2-year old juveniles was not observed. This implies that the differentiation of a penis and a vas deferens, which already occurred in the first few months after hatching, was not controlled by gonadal factors. No other sexual characteristics than those already visible with the eye were found. TBT inactivated CYP450 to its inactive form CYP420 in in vitro exposure studies with microsomal fractions of whelks. The studies have shown TBT to disrupt sexual development dose dependently in juvenile common whelks. TBT also dose dependently exerts an effect on enzymatic (CYP450) processes. Although no mechanical sterilisation was observed, reproduction might be impaired through growth reduction.
在这里，我们报告了一系列关于在（慢性）暴露于丁基锡化合物的影响下，普通宝螺（Buccinum undatum）中出现雄性化现象的发展和发生的实验。这些实验的主要目的是获得更多关于海洋环境中有机锡化合物影响的信息，这些信息可能与荷兰沿海水域中报道的 B. undatum 数量减少有关。在这些研究中，三丁基锡（TBT）剂量依赖性地诱导幼贝发育出雄性生殖器官。TBT 浓度>7ng Sn/l 会诱导幼贝出现雄性化。在一项暴露研究中，当 TBT 剂量≥4ng Sn/l 时，暴露组幼贝的生长明显低于对照组。在实验室中经过 5 年的时间，仅在对照水族箱中观察到产卵。因此，TBT 可能通过降低生长来损害宝螺的繁殖能力。结果表明，不同生命阶段对雄性化发育的敏感性不同。幼贝最敏感，青春期雌性也有反应，但成年雌性对 TBT 暴露没有反应，尽管它们在暴露时会剂量依赖性地增加其有机锡（OT）体负荷。仅在胚胎期暴露于环境 TBT 并不会导致雄性化程度增加，与未暴露的发育中的宝螺相比。组织学研究表明，由于精子管组织对（成年）雌性生殖开口的机械阻塞，没有导致绝育。在 2 岁的幼贝中没有观察到性腺发育。这意味着，阴茎和输精管的分化，已经在孵化后的头几个月发生，不受性腺因素的控制。除了肉眼已经可见的那些，没有发现其他性特征。在与宝螺微粒体部分的体外暴露研究中，TBT 将 CYP450 失活为其无活性形式 CYP420。这些研究表明，TBT 以剂量依赖的方式破坏幼贝的性发育。TBT 还以剂量依赖的方式对酶（CYP450）过程产生影响。虽然没有观察到机械性绝育，但通过降低生长可能会损害繁殖能力。
