human 22 human cell 21 leptin 21 priority journal 20 article 18 trophoblast 18 mitogen activated protein kinase 17 signal transduction 17 controlled study 16 placenta 16 Western blotting 15 2 (2 amino 3 methoxyphenyl)chromone 14 Humans 14 Leptin 14 Placenta 14 phosphatidylinositol 3 kinase 14 protein phosphorylation 13 Female 12 Pregnancy 12 explant 11 cell line 9 metabolism 9 plasmid 9 pregnancy 9 promoter region 9 protein kinase B 9 reporter gene 9 wortmannin 9 MAP Kinase Signaling System 8 choriocarcinoma 8