Effect of bladder distension on arginine vasopressin secretion in rats.

The mean baseline AVP level was significantly higher in the nighttime than in the daytime (17.21 ± 5.29 vs 11.68 ± 3.16 pg/mL, p = 0.0019). However, serum AVP levels did not change with time in the daytime or nighttime, regardless of an empty or distended bladder. We therefore concluded that AVP secretion was unaffected by bladder filling.