Objectives. In the rabbit, two of the major cellular alterations that mediate bladder dysfunction secondary to partial outlet obstruction are a decreased ability of the sarcoplasmic reticulum (SR) to store and release Ca²⁺, and mitochondrial dysfunction. The objective of the current study was to determine whether SR and mitochondrial dysfunctions are associated with symptomatic benign prostatic hyperplasia (BPH) in men.

Methods. Bladder biopsies were obtained from men with symptomatic BPH and from age-matched men with no urologic dysfunction. Each biopsy was analyzed for the following enzyme activities: malate dehydrogenase and citrate synthase (mitochondrial markers) and the sarcoplasmic reticular enzyme Ca²⁺-dependent adenosine triphosphatase (ATPase). These values were compared with the enzyme activities of control rabbit bladder smooth muscle and bladder smooth muscle obtained from rabbits subjected to 2 weeks of partial outlet obstruction.

Results. The enzymatic activities of all three enzymes are significantly lower in human bladder smooth muscle than in rabbit bladder smooth muscle. The maximal activities of all three enzymes are significantly lower in human bladder samples obtained from men with diagnosed obstructive uropathy than in men of equal age with no urologic dysfunction.

Conclusions. These studies demonstrate that similar to the response of the rabbit to partial outlet obstruction, obstructive dysfunction secondary to BPH is characterized by mitochondrial and SR dysfunction.