CS and hypertensive disorder: However, unchanged activities of two main enzymes of citric acid cycle [citrate synthase (CS) and 2-oxoglutarate dehydrogenase (Taegtmeyer and Overturf, 1988)] reflects similar to observed in SHR an unaltered rate of total energy production in spite of a shift in the myocardial metabolism toward glucose in the 1K1C model of hypertension.