Fig. 4.

IFN-γ selectively lowers the expression of DG lipase α in microglia. (a and b) DG and MG lipase activities were measured by providing [¹⁴C]DG (a) or [¹⁴C]2-AG (b) to whole-cell lysate prepared from untreated and IFN-γ-treated microglia in primary culture (100 units/ml for 18–24 h). At specific time points, lipids were chloroform-extracted and separated by thin-layer chromatography, bands with the same retention time as 2-AG (a) or arachidonic acid (AA) (c) were scraped off, and the radioactivity therein was determined by liquid scintillation. Values are mean ± SEM of 6–14 independent determinations of radioactivity (three to seven separate experiments performed in duplicate). (b and d) Quantitative RT-PCR showing mRNA levels of DG lipase (DGL) α and β (b) and MG lipase (MGL) (d). Dotted line represents levels of mRNA found in untreated microglia, and values are expressed in percent of this control and correspond to mean ± SEM of three determinations in IFN-γ-treated microglia (100 units/ml for 18–24 h).