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Changes in the activity of erythrocyte glutathione peroxidase associated with magnetic fields
The Science of the Total Environment, 73 (1988) 267-268 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
267
Short C o m m u n i c a t i o n
CHANGES IN THE ACTIVITY OF ERYTHROCYTE GLUTATHIONE PEROXIDASE ASSOCIATED WITH MAGNETIC F I E L D S
J. BRAVEN and A.S. FISHER
Department of Environmental Science, Plymouth Polytechnic, Drake Circus, Plymouth PL4 8AA (United Kingdom) (Received March 28th, 1988; accepted April 1st, 1988)
The selenium-containing enzyme glutathione peroxidase (GP) (E.C. 1.11.1.9) catalyses the reduction of hydrogen peroxide and lipid peroxides (ROOH) to the corresponding alcohols (ROH) with the accompanying oxidation of glutathione (GSH) ROOH + 2GSH GP GSSG -~- ROH + H 2 O Both hydrogen peroxide and metabolically produced hydroperoxides can be very damaging to cellular components unless removed by normal processes. A deficiency of GP in red blood cells is known to cause haemolytic anaemia (Steinberg et al., 1970) and a deficiency in platelets results in Glanzmanns Thrombocytopenia. Changes in GP activity are associated with rheumatoid disease in a conflicting manner; both Munthe et al. (1986) and Tarp (1986) have demonstrated a decreased erythrocyte GP activity in active rheumatoid disease, whereas both M~zes et al. (1987) and Braven (1988) observed an increase in the activity of the enzyme compared with normal controls. Little is known of the effect of magnetic fields on metabolic processes. Recently there has been an increase in the use of magnetic fields of the strength of I Tesla (10000 Gauss) in such clinical diagnostic techniques as Magnetic Resonance Imaging, resulting in the exposure of cellular systems to magnetic fields much higher than previously encountered. In our studies of erythrocyte glutathione peroxidase we have observed that the activity of the enzyme when subjected to a homogeneous magnetic field of 0.6 Tesla is only 86% of that observed in the absence of the magnetic field. The data for a typical experiment involving six repeat assays of an haemolysate preparation are as follows: (i) Mean activity in the absence of the magnetic field = 81.61nmol substrate/min/mg protein (standard deviation 6.63). (ii) Mean activity in 0.6 Tesla field = 70.76nmol substrate/min/mg protein (standard deviation 7.06). A comparison of the two sets of data using Students "t" test gives a p value
0048-9697/88]$03.50
© 1988 Elsevier Science Publisher.~ R.V.
268
of 0.01. The assays were carried out using the method of Floh~ and Gunzler (1984), and full data are given in Fisher (1987). We have, as yet, no explanation for the 14% lowering of GP activity in the strong magnetic field and our investigations are continuing. There is an increased awareness of the possible effects of magnetic fields on cellular systems, and in this light we feel that our observations should not pass unrecorded. REFERENCES Braven, J., 1988. Submitted. Fisher, A.S., BSc Thesis, Plymouth Polytechnic. 1987. Floh~, L. and W.A. Gunzler, 1984. Assays of glutathione peroxidase. Methods Enzymol., 105: 114-121. Mezes, M., A. P~ir,G. Bartoscewiecz and J. Nemeth, 1987. Vitamin E content and Lipid peroxidation of blood in some chronic inflammatory diseases. Acta Physiol. Hung. 69 (1): 133-138. Munthe, E., E. Jellum, J. Aaseth, A. Glennas, E. Tsui and K. Bilbow, 1988. Thiols, gold salts and selenium in the treatment of rheumatoid arthritis.In: Swaak, A.J.G. and Koster J.F. (Eds), The Radicals In Arthritic Diseases. EURAGE,Rijswijk, The Netherlands, pp. 112-128. Steinberg, M., M.J. Brauer and T.F. Necheles, 1970. Acute haemolytic anaemia associated with erythrocyte glutathione.peroxidasc deficiency. Arch. Intern. Med., 125: 302-303. Tarp, U., 1986. Selenium and glutathione peroxidase in rheumatoid arthritis.In" Swaak A.J.G. and Koster J.F. (Eds),The Radicals in Arthritic Diseases. E U R A G E , Rijswijk, The Netherlands, pp. 6,9--73.
267
Short C o m m u n i c a t i o n
CHANGES IN THE ACTIVITY OF ERYTHROCYTE GLUTATHIONE PEROXIDASE ASSOCIATED WITH MAGNETIC F I E L D S
J. BRAVEN and A.S. FISHER
Department of Environmental Science, Plymouth Polytechnic, Drake Circus, Plymouth PL4 8AA (United Kingdom) (Received March 28th, 1988; accepted April 1st, 1988)
The selenium-containing enzyme glutathione peroxidase (GP) (E.C. 1.11.1.9) catalyses the reduction of hydrogen peroxide and lipid peroxides (ROOH) to the corresponding alcohols (ROH) with the accompanying oxidation of glutathione (GSH) ROOH + 2GSH GP GSSG -~- ROH + H 2 O Both hydrogen peroxide and metabolically produced hydroperoxides can be very damaging to cellular components unless removed by normal processes. A deficiency of GP in red blood cells is known to cause haemolytic anaemia (Steinberg et al., 1970) and a deficiency in platelets results in Glanzmanns Thrombocytopenia. Changes in GP activity are associated with rheumatoid disease in a conflicting manner; both Munthe et al. (1986) and Tarp (1986) have demonstrated a decreased erythrocyte GP activity in active rheumatoid disease, whereas both M~zes et al. (1987) and Braven (1988) observed an increase in the activity of the enzyme compared with normal controls. Little is known of the effect of magnetic fields on metabolic processes. Recently there has been an increase in the use of magnetic fields of the strength of I Tesla (10000 Gauss) in such clinical diagnostic techniques as Magnetic Resonance Imaging, resulting in the exposure of cellular systems to magnetic fields much higher than previously encountered. In our studies of erythrocyte glutathione peroxidase we have observed that the activity of the enzyme when subjected to a homogeneous magnetic field of 0.6 Tesla is only 86% of that observed in the absence of the magnetic field. The data for a typical experiment involving six repeat assays of an haemolysate preparation are as follows: (i) Mean activity in the absence of the magnetic field = 81.61nmol substrate/min/mg protein (standard deviation 6.63). (ii) Mean activity in 0.6 Tesla field = 70.76nmol substrate/min/mg protein (standard deviation 7.06). A comparison of the two sets of data using Students "t" test gives a p value
0048-9697/88]$03.50
© 1988 Elsevier Science Publisher.~ R.V.
268
of 0.01. The assays were carried out using the method of Floh~ and Gunzler (1984), and full data are given in Fisher (1987). We have, as yet, no explanation for the 14% lowering of GP activity in the strong magnetic field and our investigations are continuing. There is an increased awareness of the possible effects of magnetic fields on cellular systems, and in this light we feel that our observations should not pass unrecorded. REFERENCES Braven, J., 1988. Submitted. Fisher, A.S., BSc Thesis, Plymouth Polytechnic. 1987. Floh~, L. and W.A. Gunzler, 1984. Assays of glutathione peroxidase. Methods Enzymol., 105: 114-121. Mezes, M., A. P~ir,G. Bartoscewiecz and J. Nemeth, 1987. Vitamin E content and Lipid peroxidation of blood in some chronic inflammatory diseases. Acta Physiol. Hung. 69 (1): 133-138. Munthe, E., E. Jellum, J. Aaseth, A. Glennas, E. Tsui and K. Bilbow, 1988. Thiols, gold salts and selenium in the treatment of rheumatoid arthritis.In: Swaak, A.J.G. and Koster J.F. (Eds), The Radicals In Arthritic Diseases. EURAGE,Rijswijk, The Netherlands, pp. 112-128. Steinberg, M., M.J. Brauer and T.F. Necheles, 1970. Acute haemolytic anaemia associated with erythrocyte glutathione.peroxidasc deficiency. Arch. Intern. Med., 125: 302-303. Tarp, U., 1986. Selenium and glutathione peroxidase in rheumatoid arthritis.In" Swaak A.J.G. and Koster J.F. (Eds),The Radicals in Arthritic Diseases. E U R A G E , Rijswijk, The Netherlands, pp. 6,9--73.