Differential effects of monovalent, divalent and trivalent metal ions on rat brain hexokinase

Abstract

1. The effects of monovalent (Li+ Cs+) divalent (Cu2+, Ca2+, Sr2+, Ba2+, Zn2+, Cd2+, Hg2+ Pb2+, Mn2+, Fe2+, Co2+, Ni2+) and trivalent (Cr3+, Fe3+, Al3+) metals ions on hexokinase activity in rat brain cytosol were compared at 500μM. 2. The rank order of their potency as inhibitors of brain hexokinase was: Cr3+ (IC50 = 1.3 μM) > Hg2+ = Al3- > Cu2+ > Pb2+ (IC50 = 80 μM) > Fe3+(IC50 = 250 μM > Cd2+ (IC50 = 250 μM) > Zn2+ (IC50 = 560 μM). However, at 500 μM Co2+ slightly stimulated brain hexokinase whereas the other metal ions were without effect. 3. That inhibition of brain glucose metabolism may be an important mechanism in the neurotoxicity of metals is suggested. © 1985.