Cysteine Prevents the Development of Experimental Diabetes Induced by Zinc-Binding Substances.

In experimental rabbits, cysteine injected intravenously in a dose of 1000 mg/kg temporarily bound zinc in β cells and prevented the formation of chelate zinc complexes in response to subsequent injection of diabetogenic zinc-binding substances that induce cell destruction. Injection of cysteine to animals was associated with a sharply negative reaction to zinc in β cells, which attests to blockade of zinc ions. Injection of cysteine few minutes after dithizone and formation of zinc-dithizone complex was followed by displacement of dithizone from the complex and prevented the development of diabetes in most animals. The most plausible mechanism of preventive effect of cysteine is the formation of 2:1 zinc-cysteine complex in β cells with possible fixation of Zn atom between sulfur atoms from SH groups of two cysteine molecules.