The time-dependent decreases of OGT and OGA did not coincide exactly with the dynamic changes of O-GlcNAcylation levels (up at 1 hr post ischemia and then down afterwards) in the ipsilateral side of the brain, which could otherwise explain the transient increase of global O-GlcNAcylation within four hours after cerebral ischemia. The gene discussed is OGT; the disease is brain ischemia.