GDF9 and BMP15 induce AMH expression through Smad2/3 and PI3K/Akt signaling in KGN cells. Relative expression of (A) AMH mRNA levels and (B) AMH protein levels in GDF9 + BMP15 (2.5 ng/mL) stimulated KGN cells pretreated with PKA inhibitor H89 (10 μM), PI3K inhibitor LY294002 (10 μM), MAPK inhibitor U0126 (10 μM), Smad2/3 inhibitor SB431542 (10 μM), and Smad 1/5/8 inhibitor LDN193189 (100 nM). (C, D) GDF9 + BMP15 induces (C) Smad2/3 and (D) Akt activation in KGN cells. (E) Inhibition of Smad2/3 pathway with SB431542 (10 μM) has no effect on GDF9 + BMP15–induced Akt phosphorylation. (F, G) PI3K/Akt pathway alone is not sufficient to induce AMH expression. Insulin stimulates Akt but not (E) Smad2/3 phosphorylation and has no effect on the (F) expression of AMH mRNA levels in KGN cells. AMH mRNA data are displayed as mean ± SE (n = 3 experiments) and normalized to GAPDH levels. *P ≤ 0.001 vs media. LDN, LDN193189; LY, LY294002; SB, SB431542.