In this study, we examined whether granulosa cell autophagy during follicular 
development and atresia was regulated by the class I phosphoinositide-3 
kinase/protein kinase B (AKT) pathway, which is known to control the activity of 
mammalian target of rapamycin (mTOR), a major negative regulator of autophagy. 
Ovaries and granulosa cells were obtained using an established 
gonadotropin-primed immature rat model that induces follicular development and 
atresia. Autophagy was evaluated by measuring the expression level of 
microtubule-associated protein light chain 3-II (LC3-II) using western blots and 
immunohistochemistry. The activity of AKT and mTOR was also examined by 
observing the phosphorylation of AKT and ribosomal protein S6 kinase (S6K) 
respectively. After gonadotropin injection, LC3-II expression was suppressed and 
phosphorylation of AKT and S6K increased in rat granulosa cells. By contrast, 
gonadotropin withdrawal by metabolic clearance promoted LC3-II expression and 
decreased phosphorylation of AKT and S6K. In addition, in-vitro FSH treatment of 
rat granulosa cells also indicated inhibition of LC3-II expression accompanied 
by a marked increase in phosphorylation of AKT and S6K. Inhibition of AKT 
phosphorylation using AKT inhibitor VIII suppressed FSH-mediated phosphorylation 
of S6K, followed by an increase in LC3-II expression. Furthermore, co-treatment 
with FSH and AKT inhibitor increased the levels of apoptosis and cell death of 
granulosa cells compared with the single treatment with FSH. Taken together, our 
findings indicated that AKT-mediated activation of mTOR suppresses granulosa 
cell autophagy during follicular development and is involved in the regulation 
of apoptotic cell death.