The effect of acute bladder filling on plasmatic antidiuretic hormone production in healthy adult volunteers

Objective: To assess the existence of a vesical hypothalamic reflex by evaluating the changes of plasmatic ADH levels during acute bladder filling in healthy adult volunteers. Materials and Methods: Twenty normal male subjects aged between 19 and 40 years (average age 31.6 years) were evaluated. All subjects signed informed consent. The subjects had no pathologic blood and urine examination, no cardiovascular, hepatic, renal disease, they were no smokers and they did not take drugs which may interfere with plasmatic ADH levels. A blood sampling at rest condition (time 0) and successively during cystometry in the presence of first sensation, normal and strong desire was carried out. Plasmatic ADH was measured on extracted samples by radioimmunoassay. A one-factor repeated measures analysis of variance was employed to verify the effect of time on ADH levels. The Greenhouse-Geisser and Huynh-Feldt adjustments were adopted to protect against the case of violation of homogeneity of covariance. Results: Statistical analysis did not show significant differences of plasmatic ADH levels between rest condition and bladder filling. Conclusions: We exclude the existence of a vesical hypothalamic reflex and we suppose that extravesical factors may interfere with the plasmatic ADH production during the night.