The mechanisms of action of interleukin-1 on rabbit intestinal epithelial cells

INTERLEUKIN-1 (IL-l) is an inflammatory mediator that increases Cl- secreti on in intestinal epithelial cells. To identify the signal transduction path way(s) involved in IL-l's action, cells were treated with IL-1 and the leve ls of cyclooxygenase (COX) enzymes, prostaglandin E-2 (PGE(2)) and phosphol ipase A(2)-activating protein (PLAP), and the activity of phospholipase A, (PLA(2)) were measured. IL-I caused concentration- and time-dependent incre ases in the levels of PLA(2) activity, and/or in the levels of FLAP, COX-2 and PGE(2). The IL-induced increase in PGE(2) levels was biphasic, with the first peak due to the increase in FLAP levels, and the second peak due to the increase in COX-2 levels. This increase in PGE(2) levels may provide a mechanism for acute and chronic inflammation in the intestine.