Electrochemical Investigation of Strontium–Metallothionein Interactions – Analysis of Serum and Urine of Patients with Osteoporosis

Abstract

AbstractThe main aim of this paper is to study interaction between strontium and metallothionein (MT), and to determine changes in strontium and thiols (MT, reduced glutathione, cysteine, and homocysteine) level in plasma, serum, and urine samples of patients treated with strontium ranelate (SrR). To investigate the interactions between MT and strontium(II) ions, adsorptive transfer stripping technique coupled with differential pulse voltammetry (DPV) the Brdicka reaction was employed. Besides standard Brdicka signals (Co, RS2Co, Cat1, Cat2, Cat3), we observed new signal related to Sr‐MT interaction. Further we investigated the effect of various time of interaction, concentration of strontium(II) ions and temperature of supporting electrolyte on Brdicka signals. Optimal time of interaction was 240 s. Under temperature of supporting electrolyte 20 °C, we measured linear dependence of Cat3 signal height on strontium(II) ions concentration. After that we have investigated the possibility of strontium‐MT interactions, we were interested in strontium, MT and low molecular mass thiols levels in serum and urine of patients treated with strontium(II) ions to cure osteoporosis. Strontium concentration determined by atomic absorption spectrometry was 55±5 μg/L before and 10,500±1,400 μg/L at the 30th day of SrR administration. Levels of metallothionein in serum ranged from 0.1 to 6.4 μM. Correlation between serum strontium concentration and MT level was determined and correlation coefficient was R=0.93.