Hurtt M E, Working P K
Department of Genetic Toxicology, Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709.
Fundam Appl Toxicol. 1988 Apr;10(3):490-8. doi: 10.1016/0272-0590(88)90295-3.
Methyl chloride (MeCl) and methyl bromide (MeBr) have similar target organ specificities in the male F-344 rat, and MeCl is a known reproductive toxicant in that species. Recently, both acute and subchronic inhalation exposures to MeBr were found to produce varying degrees of testicular alteration (S.L. Eustis, S.B. Haber, R.T. Drew, and R.S.H. Yang, 1986, Toxicologist, 6, 54; N. Kato, S. Morinobu, and S. Ishizu, 1986, Ind. Health, 24, 87-103; M.E. Hurtt, K.T. Morgan, and P.K. Working, 1987, Fundam. Appl. Toxicol., 9, 352-365). The present study examined the reproductive effects of MeBr in the male F-344 rat. Adult males (11-13 weeks) were exposed by inhalation to 0 or 200 ppm MeBr 6 hr/day for 5 days (first day of exposure = Day 1). Ten animals from each group were anesthetized with pentobarbital and terminated on Days 1, 3, 5, and 8. Additionally, five males from each group were killed on Days 6, 10, 17, 24, 38, 52, and 73. Plasma testosterone concentration was reduced during and immediately following exposure (Days 1, 3, 5, and 6), but returned to control levels by Day 8. Nonprotein sulfhydryl (NPSH) content of the liver and testis was reduced during exposure but returned to control levels by Day 8 (3 days postexposure). No other reproductive indices, including testis weight, daily sperm production, cauda epididymal sperm count, sperm morphology, percentage motile sperm, linear sperm velocity, and epididymal and testicular histology, were affected by MeBr exposure at any time point examined. Thus, although MeBr causes a transient decrease in plasma testosterone and testicular NPSH concentrations during acute exposure, it has no lasting effect on sperm quality or spermatogenesis in the F-344 rat.
在雄性F - 344大鼠中，氯甲烷（MeCl）和溴甲烷（MeBr）具有相似的靶器官特异性，并且MeCl是该物种中一种已知的生殖毒物。最近，发现急性和亚慢性吸入暴露于MeBr均会产生不同程度的睾丸改变（S.L.尤斯蒂斯、S.B.哈伯、R.T.德鲁和R.S.H.杨，1986年，《毒理学家》，6卷，54页；加藤直、森信夫和石津史郎，1986年，《工业卫生》，24卷，87 - 103页；M.E.赫特、K.T.摩根和P.K.沃金，1987年，《基础与应用毒理学》，9卷，352 - 365页）。本研究检测了MeBr对雄性F - 344大鼠的生殖影响。成年雄性大鼠（11 - 13周龄）通过吸入暴露于0或200 ppm的MeBr，每天6小时，持续5天（暴露第一天 = 第1天）。每组10只动物用戊巴比妥麻醉，并在第1、3、5和8天处死。此外，每组5只雄性大鼠在第6、10、17、24、38、52和73天处死。暴露期间及暴露后立即（第1、3、5和6天）血浆睾酮浓度降低，但到第8天恢复到对照水平。肝脏和睾丸的非蛋白巯基（NPSH）含量在暴露期间降低，但在第8天（暴露后3天）恢复到对照水平。在任何检测的时间点，包括睾丸重量、每日精子生成量、附睾尾部精子计数、精子形态、活动精子百分比、精子直线速度以及附睾和睾丸组织学在内的其他生殖指标均未受到MeBr暴露的影响。因此，尽管MeBr在急性暴露期间会导致血浆睾酮和睾丸NPSH浓度短暂下降，但对F - 344大鼠的精子质量或精子发生没有持久影响。
