Comparison of intrahepatic blood volume in V1aR +/+ and V1aR −/− mice A, V1aR +/+ and V1aR −/− mice fasted for more than 8 h before the ammonia tolerance test. The mice were orally administered an ammonium chloride solution, and 5, 10, 15, 20 and 30 min after the administration, the blood ammonia levels were measured using the Amicheck meter PocketChem. Significance of variation: *P < 0.05; **P < 0.01. The results are the mean ± s.e.m. of six or seven mice. B, mice fasted for 12 h were injected with indocyanine green (ICG), and their blood was collected before and 5, 10 and 15 min after the injection. The ICG concentration in plasma was calculated. The results are the means ± s.e.m. of 10 or 9 mice. Significance of variation: *P < 0.05; **P < 0.01).