Cellular localization of group IIA phospholipase A(2) in rats

It has been known that group II phospholipase A(2) (PLA(2)) mRNA and protei n are present in the homogenates of the spleen, lung, liver, and kidney in normal rats, but the cellular origin of this enzyme has not been yet identi fied. At present, five subtypes of group II PLA(2) have been identified in mammals. Antibodies or mRNA probes previously used for detecting group II P LA(2) need to be evaluated to identify the subtypes of group II PLA(2). In this study we tried to identify group IIA PLA(2)-producing cells in normal rat tissues by in situ hybridization (ISH) using an almost full-length RNA probe for rat group IIA enzyme. Group IIA PLA(2) mRNA was detected in megak aryocytes in the spleen and Paneth cells in the intestine by ISH. These cel ls were also immunopositive for an antibody raised against group IIA PLA(2) isolated from rat platelets. Group IIA PLA2 mRNA-positive cells were not d etected in lung, liver, kidney, and pancreas. Under normal conditions, grou p IIA PLA(2)-producing cells are splenic megakaryocytes and intestinal Pane th cells in rats.