Crude cortical mitochondrial samples of Sham OVX, OVXOVX + S-equol phytoSERM, and OVX + R/S-equol phytoSERM treatment groups were analyzed for protein levels of pSer232-PDH, pSer293-PDH, and total PDHE1α levels; Hippocampal homogenates samples of Sham OVX, OVXOVX + S-equol phytoSERM, and OVX + R/S-equol phytoSERM treatment groups were analyzed for protein levels of bioenergetic enzymes, including αKGDH, COXI, CVα and CVβ. A, OVX induced significantly increase in pPDH levels, which was reversed by S and R/S-equol phytoSERM treatments (*, p<0.05 compared to OVX, bars represent mean value ± SEM, n=6 per group); B, S-equol and R/S-equol regulated expression of αKGDH, COXI, CVα but not CVβ (*, p<0.05 compared to OVX, bars represent mean value ± SEM, n=6 per group).