Triptolide (T10), an extract from the traditional Chinese herb, Tripterygium wilfordii Hook F (TWHF), has been shown to attenuate the rotational behavior induced by D: -amphetamine and prevent the loss of dopaminergic neurons in the substantia nigra in rat models of Parkinson's disease. To examine if the neuroprotective effect is mediated by its stimulation of production of neurotrophic factors from astrocytes, we investigated the effect of T10 on synthesis and release of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in rat astrocyte cultures. T10 did not affect the synthesis and release of either BDNF or GDNF. However, it significantly increased NGF mRNA expression. It also increased both intracellular NGF and NGF level in culture medium. These results indicate that the neuroprotective effect of T10 might be mediated, at least in part, via a stimulation of the production and release of NGF in astrocytes.