The effect of the full bladder on vasopressin secretion in healthy young adults.

Interactions between the central nervous system, bladder and kidneys have been investigated for many years in animal studies and have shown that bladder distension, in animals, leads to decreased urine production. The objectives of the current study were to determine the effect of a full bladder on urinary output, vasopressin secretion and urine osmolality in humans. The study involved healthy volunteers. They were studied for a period of 48 hours. This period included two 24-hour studies, one involving regular and frequent voidings (to produce a minimal bladder filling) and the other voiding postponement (to produce maximal bladder distension). In contrast to enuresis studies a circadian rhythm of vasopressin secretion was observed in the males involved in this study, whereas no significant rhythm of vasopressin secretion could be detected in the female subjects. However, this study was unable to confirm that, in humans, a full bladder causes a decrease in urine production, an increase in vasopressin secretion or an increase in urine osmolality.