We measured glutamic acid decarboxylase of 67 kDa (Gad1; the enzyme responsible for the conversion of glutamate to GABA), Calb1, and Oprm in the striatum of PGC-1α −/− and R6/2 HD mice at four and twelve weeks of age (Figure 4). The gene discussed is PPARGC1A; the disease is Huntington disease.