Digital droplet PCR quantification of mRNA copy number of the genes from the GSTM, GSTP, and GSTT families (A) in livers of female and male mice. Numbers of GSTP1/2 transcripts are shown in dark red (female) or dark blue (male). For the GSTM (Gstm1-7) family, we first show copies of transcripts for the entire family (red: female; blue: male), followed by copy number for each individual gene within the family (light red: female; light blue: male). For the GSTT (Gstt1-4) family, we first show total copy number for the entire family (magenta: female; teal: male), and the copy numbers of the individual genes within this family are represented by a lighter variation of these colors. GST activity towards the substrate CDNB in liver homogenates from female (B) and male (C) livers with different Gst genotypes. Data represent means ± S.E.M.; n = 3. Data analyzed by unpaired t-test between sex for each gene; * p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001.