FBF and t-PA net release during stepwise intrabrachial artery infusions of DDAVP (7 to 21 to 70 ng/min for 5 to 5 to 15 minutes; ▪) and sodium nitroprusside (0.5 to 2.5 to 10 μg/min for 5 to 5 to 15 minutes; ○) in 4 healthy male subjects. Means and SEM error bars. Net release of t-PA increased significantly in response to DDAVP as compared with SNP (ANOVA, time × treatment interaction:P = .0003), but there was no significant difference in FBF between the two drugs.