To examine the involvement of diacylglycerol kinase (DGK) and phosphatidic acid phosphatase (PAP) in pressure overloaded cardiac hypertrophy rats were Subjected to either ascending aortic banding for 3, 7, and 28 days or sham operation. In comparison with sham-operated rats, the left ventricular (LV) weight of the aortic-banded rats increased progressively. At 28 days after surgery, the expression of DGK epsilon mRNA but not DGK xi or PAP2b mRNA in the LV myocardium significantly decreased in the aortic-banded rats compared with the sham-operated rats. DGK xi protein in the LV myocardium translocated from the particulate to the cytosolic compartment in the aortic-banded rats. Furthermore, the myocardial content of 1, 2-diacylglycerol and PKC xi protein expression in the particulate fraction of the LV myocardium significantly increased in aortic-banded rats compared with sham-operated rats. These results suggest that DGK epsilon and DGK play distinct roles in the development of pressure overloaded cardiac hypertrophy and that the two isozymes are differentially regulated. (c) 2005 Elsevier Inc. All rights reserved.