Effects on pubertal growth and reproduction in rats exposed to lead perinatally or continuously throughout development.
Effects on pubertal growth and reproduction in rats exposed to lead perinatally or continuously throughout development.
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DOI：
10.1080/009841098159312
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发表时间：
1998-02
期刊：
影响因子：
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通讯作者：
M. Ronis;T. Badger;S. Shema;P. Roberson;F. Shaikh
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文献类型：
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作者：
M. Ronis;T. Badger;S. Shema;P. Roberson;F. Shaikh
使用大鼠模型评估发育铅暴露对生殖、内分泌和生长的影响，其中在不同发育时期在饮用水中随意施用0.6%醋酸铅（w/v），以确定铅作用是否是连续暴露于金属离子的直接影响的结果，还是继发于新生儿“内分泌印记”破坏的结果。 Sprague Dawley 大鼠暴露于铅： (1) 从妊娠第 5 天到出生； (2)妊娠期、哺乳期； (3) 仅在哺乳期间； (4)从出生到成年； (5) 从妊娠 5 天到成年。测量了铅对雄性和雌性动物生殖系统发育、成年性类固醇水平以及生长速度的影响。在任何铅治疗组中，成年后代的雄性第二性器官的相对重量均未受到显着影响。相比之下，从出生到成年或从妊娠第 5 天到成年期间暴露于铅的雌性幼崽，观察到阴道开放显着延迟，发情周期被扰乱。在仅在怀孕或哺乳期接触铅的动物中没有观察到这些对女性生殖生理的影响。仅在从胎龄 5 天到一生中持续暴露于铅的雄性幼犬中观察到成年平均血清睾酮水平的显着抑制。所有在子宫内接触铅的动物的出生体重都会下降，并且所有铅处理组的平均体重均显着下降，直至断奶。生长曲线分析表明，所有铅治疗组在哺乳期间的生长率均显着降低。然而，此外，在怀孕和哺乳期间暴露于铅的雄性幼犬中，从出生或从孕龄5 d开始，青春期期间的生长速度也显着降低。任何铅治疗组的青春期后生长率均不受影响。因此，延迟女性生殖发育和抑制成年男性血清睾酮浓度需要持续接触重金属。几乎没有观察到铅对生殖或生长参数的“内分泌印记”改变的证据。早期发育（怀孕和哺乳期）期间的暴露不会对该模型产生永久性影响，除了青春期后幼犬体重小幅（10%）下降之外。
The reproductive, endocrine, and growth effects of developmental lead exposure were assessed using a rat model in which 0.6% lead acetate (w/v) was administered in the drinking water ad libitum during different developmental periods to determine if lead actions were a result of direct effects of continuous exposure to the metal ion or secondary to disrupted neonatal "endocrine imprinting." Sprague Dawley rats were exposed to lead: (1) from gestational d 5 through birth; (2) during pregnancy and lactation; (3) during lactation only; (4) from birth through adulthood; or (5) from gestational d 5 through adulthood. Lead effects were measured on the development of aspects of the reproductive system, adult sex steroid levels, and growth rates in both male and female animals. The relative weights of male secondary sex organs in adult offspring were not significantly affected in any of the lead-treated groups. In contrast, female pups exposed to lead from birth through adulthood or from gestational day 5 through adulthood were observed to have significantly delayed vaginal opening and disrupted estrus cycling. These effects on female reproductive physiology were not observed in animals where lead exposure was confined only to pregnancy or lactation. Significant suppression of adult mean serum testosterone levels was only observed in male pups exposed to lead continuously from gestational age 5 d throughout life. Lead decreased birth weight in all animals exposed in utero and mean body weights were significantly decreased in all lead-treated groups up to weaning. Analysis of growth curves revealed that all lead-treated groups had significantly reduced growth rates during lactation. However, in addition, in male pups exposed to lead during pregnancy and lactation, from birth or from gestational age 5 d, growth rates were also significantly reduced during puberty. Postpubertal growth rates were unaffected in any lead-treated group. Thus, delayed female reproductive development and suppression of adult male serum testosterone concentration required continuous exposure to the heavy metal. Little evidence was observed for an alteration of "endocrine imprinting" by lead on either reproductive or growth parameters. Exposure during early development (pregnancy and lactation) resulted in no permanent effects in this model other than small (10%) decreases in the body weight of pups postpuberty.