INDUCTION OF L-ARGININE-DEPENDENT PRODUCTION OF NITRIC-OXIDE IN BOVINE MONOCYTES BY INTERFERON-GAMMA AND LIPOPOLYSACCHARIDE

Bovine monocytes freshly isolated from peripheral blood were induced t o produce nitric oxide by exposing them to recombinant bovine interfer on gamma (rbIFN-gamma) and Escherichia coli lipopolysaccharide (LPS) i n vitro. Moderate amounts of nitric oxide were induced by rbIFN-gamma alone, but larger amounts were induced by rbIFN-gamma and LPS together . the amount being dependent on the quantity of rbIFN-gamma added. Rea ctive nitrogen intermediates (RNI) were produced within six hours, the ir concentration peaked al four days and they were detectable for at l east eight days after the cells had been stimulated with rbIFN-gamma a nd LPS. The production of RNI was diminished by the addition of N-G-mo nomethyl-L-arginine. The data suggest that bovine monocytes can produc e RNI via a pathway involving an inducible nitric oxide synthase.