Akt1 protects against germ cell apoptosis in the postnatal mouse testis following lactational exposure to 6-N-propylthiouracil

Exposure to 6-propyl-2-thio-uracil (PTU), a neonatal goitrogen, leads to increased testis size and sperm production in rodents. Akt1, a gene involved in cell survival and proliferation is also phosphorylated by thyroxine (T4). Therefore, we examined the requirement for Akt1 in germ cell survival following PTU-induced hypothyroidism. Experiments were performed using Akt1+/+, Akt1+/−, and Akt1−/− mice. PTU was administered (0.01% w/v) via the drinking water of dams from birth to PND21. At PND15, T4 serum levels were similar in all control groups, and significantly lower in all exposed groups with a dramatic decrease in Akt1−/− mice. PTU-exposed Akt1−/− testes displayed smaller tubules, increased apoptosis, delayed lumen formation, and increased inhibin B and AMH mRNA. Relative adult testis weights were similar in all exposure groups; however, no increase in daily sperm production was observed in PTU-exposed Akt1−/− mice. In conclusion, Akt1 contributes to the effects of thyroid hormone on postnatal testis development.