EFFECT OF PARTIAL URINARY OUTLET OBSTRUCTION IN THE RABBIT ON THE INCORPORATION OF ADENINE INTO ADENINE-NUCLEOTIDES IN BLADDER SMOOTH-MUSCLE

Bladder outlet obstruction induces marked morphological, functional, a nd metabolic changes within the urinary bladder. Recent studies indica te that there is a close correlation between the contractile dysfuncti on induced by partial outlet obstruction and a marked decrease in mito chondrial oxidative activity of the hypertrophied bladder tissue. The current study investigates the effect of partial outlet obstruction on adenine metabolism within the bladder tissue. After transport into th e cell, adenine becomes available as a substrate for adenine phosphori bosyl transferase (APRT), the enzyme that catalyses the non-mitochondr ial conversion of adenine into AMP. Subsequently, AMP is phosphorylate d to ADP, the phosphate acceptor in mitochondrial oxidative phosphoryl ation. The results of these studies demonstrate that partial outlet ob struction induces a significant increase in C-14-adenine uptake into t he urinary bladder smooth muscle which in turn provides substrate for APRT and results in an increase in C-14-AMP synthesis. In contrast, th e rate of incorporation of adenine into ATP + ADP was similar for both control and obstructed tissue. The activity of APRT was not significa ntly different in control and obstructed tissue. (C) 1993 Wiley-Liss, Inc.