Sterol metabolism in A1+/AD and A1−/AD mouse forebrains; 4-month-old male mice were used. (A) GC-MS analysis of cholesterol (CHOL); P = 0.04; n = 5. (B) GC-MS analysis of lanosterol (LAN), desmosterol (DES), and 24SOH. For 24SOH, P = 0.007; n = 5. (C) Sterol synthesis in vivo (P = 0.04); n = 9. (D) Fatty acid synthesis in vivo; n = 9. (E) Esterification of [3H]cholesterol in mouse brains; P = 0.0009; n = 6. (F) Immunoblot analysis and (G) quantification of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR); P = 0.001; n = 6. (H) Relative expression of HMGR mRNA analyzed by real-time PCR; P = 0.71; n = 6. (I) Relative expressions of mRNAs of SRE response genes or LXR response genes analyzed by real-time PCR. HMGR, P = 0.71; 3-hydroxy-3-methylglutaryl CoA synthase (HMGS), P = 0.24; squalene synthase (SQS), P = 0.48; lipoprotein receptor-related protein-1 (LRP), P = 0.35; LDL receptor (LDLR), P = 0.91; sterol regulatory element–binding protein 2 (SREBP2), P = 0.35; sterol regulatory element–binding protein 1 (SREBP1), P = 0.54; apolipoprotein E (APOE), P = 0.07 (i.e., the difference approached but did not reach statistical significance); ATP-binding cassette transporter subfamily A member 1 (ABCA1), P = 0.27; ABCG1, P = 0.058; ABCG4, P = 0.63; cytochrome P450 46A1 (CYP46A1), P = 0.3; n = 6. Data represent mean ± SEM. *P < 0.05; **P < 0.01; and ***P < 0.001.