Figure 2. Perfusion of the hypoxic lobe as a percentage of baseline (BL). This figure combines the findings of the two groups; data for separate groups are given in tables 1 and 2. Hypoxia (HYPO) reduced lobar blood flow. When Nomega-nitro-L-arginine methyl ester (L- NAME) was given there was a reduction of blood flow in all six animals, and nitric oxide (NO) given to the hyperoxic regions after L-NAME (NO HYPEROX + L-NAME) caused a further reduction of lobar blood flow in five of six pigs; the sixth remained at zero blood flow, Nitric oxide to the hypoxic lobe (NO LLL) resulted in a blood flow that was 66% of baseline values, whereas nitric oxide to the hypoxic lobe after L-NAME (NO LLL + L-NAME) resulted in a blood flow of 88% of baseline. When nitric oxide was given to the hype-toxic regions (NO HYPEROX), blood flow did not differ from HYPO. Comparisons with baseline (**P < 0.01) and with hypoxia (#P < 0.05 and ##P < 0.01) were performed with analysis of variance for repeated measurements and Fisher's test of least significant difference. Star = individual data given in Figure 3.