Background The problem of the dependence between concentration of uridine (UR) and uric acid (UA) in blood plasma is very interesting taking into considerations the results ofT. Yammamoto's (1997) work, which suggested the treatment ofUR in plasma as a marker ofincreased production of UA ("overproduction") - usefull in diagnosis of hyperuricemia which is dependent on excretion of this compound. Smooth muscles ofblood vessels are characterised by proportionally high level of UTP compared with ATP If hypoxanthine (Hx) is considered as a marker ofdegradation ofATP for skeletal muscles, similarly UR may be a marker of degradation ofUTP in conditions ofhigh vasoconstriction. Moreover, it is known, that uridine nucleotides act as vasoconstrictors, and this effect is eliminated by infusion of adenosine.
Aim To find out whether and which correlations are there between concentration ofUR in plasma and concentration ofUA and its precursors eg. Hx and X (xanthine) as well as insulin.
Material Patients with essential hypertension (HT) - 36 persons (24 M and 12 F), aged 41,8 ± 16,2. The control group (GK) -37 healthypeople-volunteeries (21 M,14 F), aged 39,4 ± 12,5.
Methods The concentration ofUA, Hx, X and UR in plasma was determined using the HPLC method. The level of immunoreactive insulin (INS) in serum was determined by RIA - INS kits (Centralny Ośrodek Badawczo-Rozwojowy Izotopów, Świerk/Otwock, Poland).
Results 1. Statistically significant differences in concentrations ofUA and Hx in plasma in HT as compared with CG in which these concentrations were lower. 2. The concentration of UR in HT was lower than in GK. 3. A high significant correlations between Hx and UR and X and UR were obtained in both group. Such correlation was not observed between the UA and UR concentrations in plasma. 4. The dependence between UR and INS was found only in the HT group, where the concentration of INS was higher than in GK.
Conclusions 1. The plasma level of uridine is not a marker of hyperuricemia in essential hypertension. 2. Hyperinsulincmia in hypertension is associated with disturbances in metabolism of purines and pyrimidines.