Quinn Anne L, Dalu Abe, Meeker Linda S, Jean Paul A, Meeks Robert G, Crissman James W, Gallavan Robert H, Plotzke Kathleen P
Dow Corning Corporation, Midland, MI 48686-0994, United States.
Reprod Toxicol. 2007 Jun;23(4):532-40. doi: 10.1016/j.reprotox.2007.02.005. Epub 2007 Mar 2.
The objectives of this study were to assess the potential for D(4) to suppress the pre-ovulatory lutenizing hormone (LH) surge, to block or delay ovulation, and to evaluate potential effects on reproductive hormones in rats. Female Sprague-Dawley Crl:CD (SD) IGS BR rats received whole-body vapor inhalation exposure to D(4) (0, 700, or 900ppm) 6h per day for 3 days. Trunk blood obtained on proestrus at 10a.m. was evaluated for levels of follicle stimulating hormone (FSH), estradiol (E2), estrone (E1), and progesterone (P4). Other rats had serial blood samples collected via cannula at 2, 4, 6, 8, and 10p.m. on the day of proestrus and plasma evaluated for LH and prolactin (PRL). Trunk blood was collected at 8a.m. of estrus and plasma evaluated for FSH, E2, E1, and P4. At 10a.m. on proestrus, significant increases in E1 levels in the 700 and 900ppm groups and significant increases in P4 levels in the 900ppm group were noted. At 8a.m. on estrus, significant increases in E1, E2, in the E1/E2 ratio and decreases in FSH were noted in the 700 and 900ppm groups. The major effect on the LH profile was observed most clearly when the rats were grouped by ovulatory status, animals that did or did not ovulate. Regardless of treatment, suppression of the LH surge correlated with blocked ovulation. The percentage of rats that ovulated was (700ppm, 42%; 900ppm, 31%) compared to controls (79%). Overall, the data indicate that high exposures to D(4) attenuated the pre-ovulatory LH surge and significantly decreased the portion of female rats that ovulated.
本研究的目的是评估D(4)抑制排卵前促黄体生成素（LH）激增、阻止或延迟排卵的可能性，并评估其对大鼠生殖激素的潜在影响。雌性斯普拉格-道利Crl:CD（SD）IGS BR大鼠每天接受6小时的全身蒸汽吸入暴露于D(4)（0、700或900ppm），持续3天。在发情前期上午10点采集的躯干血用于评估促卵泡激素（FSH）、雌二醇（E2）、雌酮（E1）和孕酮（P4）的水平。其他大鼠在发情前期当天下午2点、4点、6点、8点和10点通过插管采集系列血样，并评估血浆中的LH和催乳素（PRL）。在发情期上午8点采集躯干血，并评估血浆中的FSH、E2、E1和P4。在发情前期上午10点，700ppm和900ppm组的E1水平显著升高，900ppm组的P4水平显著升高。在发情期上午8点，700ppm和900ppm组的E1、E2、E1/E2比值显著升高，FSH降低。当根据排卵状态对大鼠进行分组时，即排卵或未排卵的动物，对LH曲线的主要影响最为明显。无论治疗如何，LH激增的抑制与排卵受阻相关。与对照组（79%）相比，排卵的大鼠百分比为（700ppm，42%；900ppm，31%）。总体而言，数据表明高剂量暴露于D(4)会减弱排卵前LH激增，并显著降低排卵的雌性大鼠比例。
