Evidence that angiotensin II is present in human monocytes

Abstract

Background: The purpose of the present study was to determine whether human monocytes and polymorphonuclear leukocytes contain angiotensins I and II.

Methods and results: Human mononuclear and polymorphonuclear leukocytes were isolated from blood. To identify angiotensins in human leukocytes, we performed immunocytochemistry using both alkaline phosphatase and fluorescence methods. With light microscopy immunocytochemistry with alkaline phosphatase, prominent staining of angiotensin II was observed in mononuclear leukocytes. Angiotensin I was also demonstrated in mononuclear leukocytes, but the signal was less pronounced than for angiotensin II. Polymorphonuclear leukocytes showed very little staining for angiotensin II. Fluorescence immunocytochemistry also demonstrated angiotensin II in mononuclear leukocytes. Angiotensins I and II in homogenate of leukocytes were quantified by radioimmunoassay. The concentration of angiotensins I and II in mononuclear leukocytes was 355 +/- 216 (mean +/- SEM) and 2331 +/- 106 fmol/mg protein, respectively, and the concentration in polymorphonuclear leukocytes was 36 +/- 10 and 336 +/- 120 fmol/mg protein.

Conclusions: These findings suggest that human mononuclear leukocytes contain large amounts of angiotensin II and lesser amounts of angiotensin I. Human polymorphonuclear leukocytes contain small amounts of angiotensin I and II.