Chaleil D, Lefevre F, Allain P, Martin G J
J Inorg Biochem. 1981 Nov;15(3):213-21. doi: 10.1016/s0162-0134(00)80156-7.
In a preliminary paper [Thérapie 34, 397 (1979), we showed that cysteine enhances bismuth digestive absorption in rats. In this paper, we have studied in rats the effects of various thiol compounds (mercaptopropionic acid, penicillamine, cysteine, homocysteine, 2-mercaptoethylamine, mercaptoethane) and nonthiol compounds (methionine, serine, alanine) orally administered on the absorption and elimination of bismuth also given orally. Bismuth was measured in blood and urine by electrothermal atomic absorption spectrophotometry. All of the thiol substances, and particularly cysteine, homocysteine, and mercaptopropionic acid, have considerably enhanced bismuth absorption and elimination; whereas, nonthiol substances have had no effect. Moreover, the acute toxicity of bismuth was enhanced when bismuth was given as a complex with cysteine (LD50 = 156 +/- 20 mg/kg). Studies by nmr spectroscopy of interactions between bismuth and these organic compounds have shown that bismuth induces an important chemical shift of the protons of the alpha carbon of the sulfhydrile group. Mainly, studies of C and N have confirmed this fact. The selectivity of such a complexation, in our pH conditions, may be tentatively explained on the ground of hard and soft acid and base (HSAB) theory. We have suggested that an increase in the concentration of thiol compounds in the gastrointestinal tract arising from food, or more probably from microorganism synthesis, could be an explanation for human encephalopathies.
在一篇初步论文中[《治疗学》34卷，397页（1979年）]，我们表明半胱氨酸可增强大鼠对铋的消化吸收。在本文中，我们研究了经口给予大鼠各种硫醇化合物（巯基丙酸、青霉胺、半胱氨酸、同型半胱氨酸、2-巯基乙胺、巯基乙烷）和非硫醇化合物（蛋氨酸、丝氨酸、丙氨酸）对经口给予的铋的吸收和消除的影响。通过电热原子吸收分光光度法测定血液和尿液中的铋。所有硫醇物质，尤其是半胱氨酸、同型半胱氨酸和巯基丙酸，均显著增强了铋的吸收和消除；而非硫醇物质则无此作用。此外，当铋与半胱氨酸形成复合物给予时，铋的急性毒性增强（半数致死量=156±20毫克/千克）。通过核磁共振光谱研究铋与这些有机化合物之间的相互作用表明，铋会引起巯基α碳原子上质子的重要化学位移。主要通过对碳和氮的研究证实了这一事实。在我们的pH条件下，这种络合作用的选择性可根据软硬酸碱（HSAB）理论初步解释。我们认为，食物中，更可能是微生物合成产生的胃肠道中硫醇化合物浓度的增加，可能是人类脑病的一个解释。
