Role of PI3K-Akt pathway in IGF-I-stimulated kitlga expression in cultured zebrafish follicle cells. A, Time course of IGF-I activation of Akt in the follicle cells (upper) and blockade of IGF-I-induced Akt phosphorylation by specific PI3K inhibitors, LY294002 and wortmannin (lower). Cultured zebrafish follicle cells were pretreated with LY294002 (50 μM) or wortmannin (500 nM) for 30 minutes before treatment with IGF-I (50 ng/mL) for 15 minutes. p-Akt, phosphorylated Akt; t-Akt, total Akt. B–D, Effect of IGF-I on the expression of kitlga in the presence of LY294002 (50 μM), wortmannin (500 nM) or Akti (10 μM) in cultured zebrafish follicle cells. The cells were pretreated with the drugs for 30 minutes before treatment with IGF-I (50 ng/mL) for 6 hours. E–H, Dose response of LY294002, wortmannin, and Akti effects on the basal expression of kitlga in cultured zebrafish follicle cells after 6 hours of treatment. The data were normalized to the housekeeping gene ef1a and expressed as the percentage of the control group (mean ± SEM; n = 4). Statistical significance was indicated by asterisk (***, P < .001) or different letters (P < .05).