Effect of thyroid releasing hormone on bladder and urethral pressures.

In order to explain the pathophysiology of urinary urgency frequency observed following the administration of thyroid releasing hormone (TRH) during thyroid function testing, simultaneous urethrocystometry was performed in six females before and after TRH administration, and in another five females before and after administration of normal saline (control group). Within a few minutes following TRH administration, a statistically significant and consistent drop in maximal urethral pressure and concomitant sensation of urinary urgency in the absence of significant changes in true detrusor pressure suggested the presence of a reflex neuronally mediated motor component to this sensory effect of urinary urgency. The absence of urethral and detrusor pressure changes in the control group reinforced the TRH-mediated origin of urinary urgency.