Glucocorticoid receptor, Oestrogen receptor, LXRα
(20S)-Protopanaxatriol works through the glucocorticoid receptor (GR) and oestrogen receptor (ER) in human umbilical vein endothelial cells (HUVECs). (20S)-Protopanaxatriol (g-PPT) increases [Ca 2+ ] i with an EC 50 of 482 nM in HUVECs. (20S)-Protopanaxatriol (1 µM) elevates NO production via ERβ. (20S)-Protopanaxatriol (PPT) inhibits the autonomous transactivation of Gal4-LXRα LBD, the T0901317-dependent transcription of SREBP-1c and its promoter. (20S)-Protopanaxatriol (10 μg/mL) blocks the recruitment of RNA polymerase II to the LXRE region of SREBP-1c. (20S)-Protopanaxatriol also inhibits T0901317-dependent transcription of LXRα target genes related to lipogenesis, and reduces T0901317-induced cellular triglyceride (TG) accumulation in primary hepatocytes, but does not alter transcription of ABCA1, also an LXRα target gene.