RESUMO
In experimental rabbits, cysteine injected intravenously in a dose of 1000 mg/kg temporarily bound zinc in ß 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 ß 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 ß cells with possible fixation of Zn atom between sulfur atoms from SH groups of two cysteine molecules.
Assuntos
Cisteína/uso terapêutico , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/prevenção & controle , Ditizona/efeitos adversos , Zinco/metabolismo , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Cisteína/farmacologia , Citoproteção/efeitos dos fármacos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Ditizona/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , CoelhosRESUMO
Long-term administration of pyridoxine to rats kept on a diabetogenic diet stimulating endogenous synthesis of xanthurenic acid resulted in minimal glycemia, less pronounced decrease in insulin content in ß-cells, and more intensive excretion of xanthurenic acid with urine. Histological changes were observed in 23% pancreatic islets, whereas in rats not treated with pyridoxine, destruction and necrosis of 40-45% ß-cells were found in 38% of studied islets.
