Objective: Increase in plasma hypoxanthine (HX)(purine nucleotide degradation product fromworking muscle) reflects insufficiency of ATPsupply during exercise. This study investigated the plasma HX responseduring exercise in patients with essential hypertension(HT). Methods: Heart rate, blod pressure(BP) response and plasma HX levels were measured during and after submaximal treadmill exericise (modified Bruce protocl) in 17patients with HT. Patients were divided intotwo groups (ExcessiveBP response group (n=6); A peak systolic BP≥72mm Hg, and Normal response group(n=11); Δpeak systolicBP<72mm Hg). Results: The excessive BP responsegroup showed the following results comparedto those of Normal BP response group; (1) Body mass index wasgreater (Normal BPresponse group vs Excessive BP response group: 23±2 vs 28±6kg/m2 p<0.05), (2) Heart rate response to exercise was similar betweenthe two groups, but systolic and diastolic BPresponses were higher (209±18/102±9 vs 244±25/118±16mm Hg, p<0.05), (3) increments in plasma HX from rest to 10minuteafter exercise (ΔHX-P10)was significantlyhigher (0.31±0.20vs 0.79±0.34μg/ml, p<0.05), and resting plasma uric acid was significantly higher (4.7±1.6 vs 7.1±1.4 mg/dl, p<0.05), (4)Left ventricular hypertrophywas more prevalent in patients with an ExcessiveBP response group (27% vs 83%, p<0.05), (5) There was a positive correlation between HX-P10 and plasma uric acid levels in all hypertensive patients (r=0.53, p<0.05). Conclusion: Patients with essential HT with excessive BP response during exercise were characterized bythe presence of obesity, hypertension, and leftyentricular hypertropyh. These patients showedexcessive purine nucleotide degradation duringexercise. These augumented purine catabolismduring exercise may relate to hyperuricemiainthese patients with HT.
Hyperuricemia is frequently associated with multiple risk factor clustering syndrome, and consequently, carries a potential risk of cardiovascular disease. We previously reported on the Consensus Conference on Management of Hyperuricemia and Gout in Japan (February,1996). The present study examined trends in the management of hyperuricemia by general practitioners in contrast to that of the specialists using an anonymous questionnaire. Proper guidelines were shown to be necessary for general practitioners, who do not possess any definite criteria for serum urate levels in managing hyperuricemia. We consider that there are needs for lifelong therapy, theim portance of evaluating renal urate handling status, that urine alkalization is beneficial, and the need for laboratory examination with consideration to cardiovascular events. We specialists, therefore, should emphasige the neccessity of uniform methods of managing a hyperuricemia in daily practice.