Administration of a hydroxamate inhibitor of MMPs and ADAMs promotes neutrophil emigration to an extent similar to Adam17^−/− chimeras, but does not alter monocyte emigration. (A) Neutrophil emigration in C57BL/6 mice treated with a hydroxamate inhibitor or vehicle (n = 4 per group) was monitored as described in the legend to Figure 1. The experiment shown is representative of a total of 3 experiments. *P = .01. (B) Neutrophil emigration into the peritoneal cavity of Adam17^+/+ and Adam17^−/− chimeras was analyzed in the presence and absence of the hydroxamate inhibitor 4 hours after thioglycollate injection. **P < .0001. (C) Time course of monocyte emigration in C57BL/6 mice in the presence and absence of hydroxamate inhibitor as described in panel A is shown using an antibody to F4/80 to identify macrophages. (D) Monocyte emigration into the peritoneal cavity of Adam17^+/+ and Adam17^−/− chimeras was analyzed in the presence and absence of the hydroxamate inhibitor 16 hours after thioglycollate injection. **P < .0001. All data are expressed as means ± SD.