Summary
Malondialdehyde (MDA) is a stable product of arachidonic acid metabolism, catalyzed by the enzyme cyclo-oxygenase. The experimental conditions for measuring the kinetic of MDA formation in rat platelet-rich plasma were defined. In platelets stimulated with arachidonic acid MDA formation was almost linear for a limited period of time (between 0 and 2 min) and was concentration-dependent with saturation kinetics. The hyperbolic curves obtained were recast in a linear plot (according to transformation S/V versus S) and straight lines fitting all experimental points were obtained. The apparent K m value of arachidonic acid was 0.49±0.09 mM and V max 1.44±0.06 nmoles MDA/1.4×109 platelets/min.
The apparent type of inhibition and the relative potency of acetylsalicylic acid and indomethacin on MDA formation were also investigated. Inhibition by both drugs was concentration-dependent, and was much stronger when either drug was preincubated with platelets for 10 min than for 1 min. Analysis of the data by Dixon plots (1/V versus inhibitor concentrations) revealed an apparently competitive type of inhibition.
It is suggested that both acetylsalicylic acid and indomethacin inhibit cyclo-oxygenase in platelet-rich plasma by a similar mechanism, not involving covalent binding of either drug to the enzyme.
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References
Cheng, Y.-C., Prusoff, W. H.: Relationship between the inhibition constant (Ki) and the concentration of inhibitor which causes 50 percent inhibition (I50) of an enzymatic reaction. Biochem. Pharmacol. 22, 3099–3108 (1973)
de Gaetano, G.: Pharmacological properties of drugs inhibiting platelet aggregation. Acta Clin. Belg. 30, 184–189 (1975)
de Gaetano, G., Donati, M. B., Vermylen, J.: Some effects of indomethacin on platelet function, blood coagulation and fibrinolysis. Int. J. Clin. Pharmacol. Ther. Toxicol. 5, 196–199 (1971)
Dixon, M.: The determination of enzyme-inhibitor constants. Biochem. J. 55, 170–171 (1953)
Dormandy, T. L.: Free-radical oxidation and antioxidants. Lancet 1, 647–650 (1978)
Egan, R. W., Paxton, J., Kuehl, F. A., Jr.: Mechanism for irreversible self-deactivation of prostaglandin synthetase. J. Biol. Chem. 251, 7329–7335 (1976)
Flower, R. J.: Drugs which inhibit prostaglandin biosynthesis. Pharmacol. Rev. 26, 33–67 (1974)
Hamberg, M., Svensson, J., Samuelsson, B.: Prostaglandin endoperoxides. A new concept concerning the mode of action and release of prostaglandins. Proc. Natl. Acad. Sci. USA 71, 3824–3828 (1974)
Kocsis, J. J., Hernandovich, J., Silver, M. J., Smith, J. B., Ingerman, C.: Duration of inhibition of platelet prostaglandin formation and aggregation by ingested aspirin or indomethacin. Prostaglandins 3, 141–144 (1973)
Mahler, H. R., Cordes, E. H.: Biological Chemistry. New York: Harper and Row 1966
Merino, J., Livio, M., Rajtar, G., de Gaetano, G.: Reversibility of in vitro aspirin inhibition of platelet and vascular prostaglandin generation. Biochem. Pharmacol. (in press 1980)
O'Brien, J. R.: Effect of anti-inflammatory agents on platelets. Lancet 1, 894–895 (1968)
Okuma, M., Steiner, M., Baldini, M.: Studies on lipid peroxides in platelets. I. Method of assay and effect of storage. J. Lab. Clin. Med. 75, 283–296 (1970)
Riegelman, S.: The kinetic disposition of aspirin in human. In: Aspirin, platelets and stroke, background for a clinical trial. (W. S. Fields, W. K. Hass, eds.), pp. 105–114. St. Louis, Mo: Warren H. Green Inc. 1971
Rome, L. H., Lands, W. E. M.: Structural requirements for time-dependent inhibition of prostaglandin biosynthesis by antiin-flammatory drugs. Proc. Natl. Acad. Sci. USA. 72, 4863–4865 (1975)
Roth, G. J., Majerus, P. W.: The mechanism of the effect of aspirin on human platelets. I. Acetylation of a particulate fraction protein. J. Clin. Invest. 56, 624–632 (1975)
Roth, G. J., Stanford, N., Majeurs, P. W.: Acetylation of prostaglandin synthase by aspirin. Proc. Natl. Acad. Sci. USA 72, 3073–3076 (1975)
Samuelsson, B., Goldyne, M., Granström, E., Hamberg, M., Hammarström, S., Malmsten, C.: Prostaglandins and thromboxanes. Annu. Rev. Biochem. 47, 997–1029 (1978)
Silver, M. J., Smith, J. B., Ingerman, C., Kocsis, J. J.: Arachidonic acid-induced human platelet aggregation and prostaglandin formation. Prostaglandins 4, 863–875 (1973)
Smith, J. B., Ingerman, C. M., Silver, M. J.: Malondialdehyde formation as an indicator of prostaglandin production by human platelets. J. Lab. Clin. Med. 88, 167–172 (1976)
Smith, J. B., Silver, M. J.: Prostaglandin synthesis by platelets and its biological significance. In: Platelets in biology and pathology (J. L. Gordon, ed.), pp. 331–352. Amsterdam: North-Holland 1976
Smith, W. L., Lands, W. E. M.: Oxygenation of polyunsaturated fatty acids during prostaglandin biosynthesis by sheep vesicular gland. Biochemistry 11, 3276–3285 (1972)
Stanford, N., Roth, G. J., Shen, T. Y., Majerus, P. W.: Lack of covalent modification of prostaglandin synthetase (cyclooxygenase) by indomethacin. Prostaglandins 13, 669–675 (1977)
Sturman, J. A., Smith, M. J. H.: The binding of salicylate to plasma proteins in different species. J. Pharm. Pharmacol. 19, 621–622 (1967)
Vargaftig, B. B.: The inhibition of cyclo-oxygenase of rabbit platelets by aspirin is prevented by salicylic acid and by phenanthrolines. Eur. J. Pharmacol. 50, 231–241 (1978)
Villa, S., Livio, M., de Gaetano, G.: The inhibitory effect of aspirin on platelet and vascular prostaglandins in rats cannot be completely dissociated. Br. J. Haematol. 42, 425–431 (1979)
Wielosz, M., Salmona, M., de Gaetano, G., Garattini, S.: Uptake of 14C-5-hydroxytryptamine by human and rat platelets and its pharmacological inhibition. A comparative kinetic analysis. Naunyn-Schmiedeberg's Arch. Pharmacol. 296, 59–65 (1976)
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de Gaetano, G., Rajtar, G., Livio, M. et al. Arachidonic acid-induced malondialdehyde formation in rat platelets. Naunyn-Schmiedeberg's Arch. Pharmacol. 312, 85–89 (1980). https://doi.org/10.1007/BF00502579
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DOI: https://doi.org/10.1007/BF00502579