The concentrations of dolichyl phosphate are also increased, while cholesterol remains unchanged. The isoprenoid changes in Alzheimer's disease differ from those occurring during normal aging, and, therefore, this disease cannot be regarded as a result of premature aging.[4] The increase in the sugar carrier dolichyl phosphate may reflect an increased rate of glycosylation in the diseased brain, and the increase in the endogenous anti-oxidant ubiquinone an attempt to protect the brain from oxidative stress, for instance, induced by lipid peroxidation.[5]