Effects of neonatal hypothyroidism on testicular development and undifferentiated spermatogonia in prepubertal rats

This study demonstrated that even low-dose transient hypothyroidism during the neonatal period enhances the population of undifferentiated germ cells, potentially including spermatogonial stem cells. The transient hypothyroidism model offers a physiologically relevant and minimally invasive platform to explore how early thyroid hormone imbalances influence germ cell population establishment during a critical window of testicular development, potentially reflecting the clinical scenarios of treated congenital hypothyroidism.