THE ACTION OF METHYLMERCURY ON THE CELL MEMBRANES

I. PERMEABILITY OF METHYLMERCURY ACROSS THE CELL MEMBRANES IN DIRECT COMPARISON WITH MERCURY CHLORIDE

Abstract

The permeabilities of methylmercury and inorganic mercury chloride across human red cell membranes were compared using Hg²⁰³ compounds. Methylmercury incorporation reached maximum even at 37° and 0°C in 3 min in the range from 80 to 90%. Methylmercury incorporation at concentrations of 10^-8, 10^-6 and 10^-4M was the same, but mercury chloride incorporation at 10^-6 and 10^-8 was lower. Cysteine inhibited the incorporation of methylmercury and mercury chloride, but DTT was not so effective. Plasma proteins inhibited the incorporation of methyl-mercury only slightly, but that of mercury chloride strongly. EDTA did not in-hibit the methylmercury incorporation in contrast to mercury chloride. Methyl-cobalamine did not affect the incorporation of methylmercury and mercury chloride even at 37° and 0°C, with or without plasma proteins for at least 60 min. After the incubation of mercury chloride with methylcobalamine the Hg²⁰³ mercury chloride was nearly completely changed into methylmercury in the absence of red cells. Binding of methylmercury to cell membranes was estimated. The values were slightly but significantly larger than that to hemoglobin on the basis of protein weight.