Increased leukotriene A(4) hydrolase expression in the heart of angiotensin II-induced hypertensive rat

Leukotriene A(4) (LTA(4)) hydrolase is essential for the conversion of LTA( 4) to LTB4, an inflammatory lipid mediator, We investigated whether LTA(4) hydrolase was regulated in the heart by angiotensin II (ang IT) infusion. C ontinuous ang II infusion via an osmotic minipump for up to 7 days upregula ted mRNA and protein levels of LTA(4) hydrolase (similar to 3.5-fold of con trol) in the heart in a presser-dependent manner. Immunohistochemistry demo nstrated intense LTA(4) hydrolase staining in the myofibroblast as well as migrated monocytes/macrophages. These data suggest that the cardiac LTA(4) hydrolase-LTB4 system plays a positive role in the promotion of cardiac inf lammation in hypertension. (C) 1999 Federation of European Biochemical Soci eties.