Rat brain 3-hydroxy-3-methylglutaryl-CoA reductase: subcellular distribution and cold lability

Data are provided indicating that the rat brain 3-hydroxy-3-methylglutarhyl-CoA reductase is similar to the enzyme from other tissues as far as diurnal rythmicity, cold lability and half-life measurements of 0 degrees C are concerned. The enzyme activity in the brain decreased with age of the animals. Subcellular fractionation studies demonstrate that while 77% of the activity was associated with the microsomal fraction, 19% of the enzyme activity was recovered in the mitochondrial fraction. The possible function of such a mitochondrially located 3-hydroxy-3-methylglutaryl-CoA reductase in rat brain is discussed.