Department of Psychology, Southwestern University, Georgetown, TX, 78626, USA.
Department of Psychology, Southwestern University, Georgetown, TX, 78626, USA.
Physiol Behav. 2022 Oct 1;254:113879. doi: 10.1016/j.physbeh.2022.113879. Epub 2022 Jun 12.
The present study examined the long-term effects of suppressing puberty with a GnRH agonist on reproductive physiology and behavior in female rats. We have recently reported that administration of the GnRH agonist leuprolide acetate (25 µg/kg) daily between postnatal day (PD) 25-50 delayed puberty and disrupted the development of copulatory behavior and sexual motivation in male rats. However, pilot data from our lab suggest that this low dose of leuprolide acetate (25 µg/kg) was not high enough to significantly delay puberty in female rats. Therefore, we injected female Long-Evans rats with leuprolide acetate at a higher dose (50 µg/kg) or 0.9% sterile saline, daily , starting on PD 25 and ending on PD 50. Vaginal opening was monitored daily starting on PD 30 for signs of pubertal onset and first estrous cycle. In addition, we measured estrous cyclicity starting approximately 2 weeks after the last injection of leuprolide (∼PD 64). Immediately after monitoring estrous cyclicity, the female rats were mated on their first day in behavioral estrus using the partner-preference paradigm, with and without physical contact (PD 95-110). We found that this dose of leuprolide (50 µg/kg) significantly delayed puberty; however, neither estrous cyclicity nor sexual motivation was significantly affected by periadolescent exposure to leuprolide. Together with our findings in male rats, these results add to our understanding of the developmental effects of chemically suppressing puberty in rats.
本研究探讨了用 GnRH 激动剂抑制青春期对雌性大鼠生殖生理学和行为的长期影响。我们最近报道，在出生后第 25-50 天期间每天给予 GnRH 激动剂亮丙瑞林乙酸酯（25 µg/kg）可延迟青春期，并破坏雄性大鼠交配行为和性动机的发育。然而，我们实验室的初步数据表明，这种低剂量的亮丙瑞林乙酸酯（25 µg/kg）不足以显著延迟雌性大鼠的青春期。因此，我们每天给长耳大仓鼠注射亮丙瑞林乙酸酯（50 µg/kg）或 0.9%无菌生理盐水，从出生后第 25 天开始，到第 50 天结束。从出生后第 30 天开始，每天监测阴道开口，以观察青春期开始和第一次发情周期的迹象。此外，我们在最后一次亮丙瑞林注射后大约 2 周（约 PD 64）开始测量发情周期。在监测发情周期后，雌性大鼠在性行为发情的第一天（PD 95-110）使用伴侣偏好范式进行交配，有无身体接触。我们发现，这种剂量的亮丙瑞林（50 µg/kg）显著延迟了青春期；然而，青春期前接触亮丙瑞林对发情周期和性动机都没有显著影响。结合我们在雄性大鼠中的发现，这些结果增加了我们对大鼠青春期化学抑制的发育影响的理解。
