Lehman-McKeeman L D, Rodriguez P A, Caudill D, Fey M L, Eddy C L, Asquith T N
Miami Valley Laboratories, Procter and Gamble Company, Cincinnati, Ohio 45239-8707.
Toxicol Appl Pharmacol. 1991 Mar 1;107(3):429-38. doi: 10.1016/0041-008x(91)90306-y.
Acute oral dosing of 3,5,5-trimethylhexanoyloxybenzene sulfonate (THBS) to adult male and female rats causes a male rat-specific nephrotoxicity manifested as exacerbation of hyaline droplet formation. This chemical is structurally distinct from the volatile hydrocarbons known to cause male rat-specific kidney lesions. Therefore, to classify THBS as a hyaline droplet-inducing agent, experiments were conducted to determine whether [14C]THBS equivalents bound to alpha 2 mu-globulin and caused the protein to accumulate in male rat kidney cortex. Two-dimensional gel electrophoretic separation of male rat kidney proteins indicated that alpha 2u-globulin levels in kidney increased 24 hr after a single oral dose of THBS (500 mg/kg). Furthermore, a sex-dependent retention THBS was noted as there was approximately 10 times more THBS equivalents in male rat kidney than in female rat kidney. Equilibrium dialysis experiments indicated that 40% of THBS equivalents bound reversibly to male rat kidney proteins, whereas no interaction between THBS and female rat kidney proteins was detected. Specific binding of THBS to alpha 2mu-globulin was determined by anion-exchange HPLC after which metabolites in the alpha 2u-globulin fraction were identified by gas chromatography with parallel radioactivity-mass spectrometry and mass spectrometry-matrix isolation Fourier-transform infrared analysis. Four metabolites of THBS were found in this protein fraction, and the major component (approximately 70%) was identified as the cis gamma-lactone of 3,5,5-trimethylhexanoic acid. Experiments were also conducted in mice to determine whether THBS bound to any mouse kidney proteins, particularly mouse urinary protein. The results indicated that there was no interaction between THBS and mouse urinary protein, a protein which shares significant homology with alpha 2u-globulin. These results indicate that THBS treatment exacerbates hyaline droplet formation in male rat kidneys by binding to alpha 2mu-globulin, thereby causing the protein to accumulate in the renal cortex. The interaction between THBS and alpha 2mu-globulin appears to be unique to this male rat-specific protein as THBS does not interact with a very similar protein found in mice.
给成年雄性和雌性大鼠急性口服3,5,5-三甲基己酰氧基苯磺酸盐（THBS）会导致雄性大鼠特有的肾毒性，表现为透明滴形成加剧。这种化学物质在结构上与已知会导致雄性大鼠特异性肾脏病变的挥发性烃类不同。因此，为了将THBS归类为诱导透明滴的物质，进行了实验以确定[14C]THBS等效物是否与α2μ-球蛋白结合并导致该蛋白质在雄性大鼠肾皮质中积累。雄性大鼠肾脏蛋白质的二维凝胶电泳分离表明，单次口服THBS（500mg/kg）后24小时，肾脏中的α2u-球蛋白水平升高。此外，注意到THBS存在性别依赖性潴留，因为雄性大鼠肾脏中的THBS等效物比雌性大鼠肾脏中的多约10倍。平衡透析实验表明，40%的THBS等效物与雄性大鼠肾脏蛋白质可逆结合，而未检测到THBS与雌性大鼠肾脏蛋白质之间的相互作用。通过阴离子交换HPLC测定THBS与α2μ-球蛋白的特异性结合，之后通过气相色谱结合平行放射性-质谱和质谱-基质隔离傅里叶变换红外分析鉴定α2u-球蛋白部分中的代谢物。在该蛋白质部分中发现了THBS的四种代谢物，主要成分（约70%）被鉴定为3,5,5-三甲基己酸的顺式γ-内酯。还在小鼠中进行了实验，以确定THBS是否与任何小鼠肾脏蛋白质结合，特别是小鼠尿蛋白。结果表明，THBS与小鼠尿蛋白之间没有相互作用，小鼠尿蛋白是一种与α2u-球蛋白具有显著同源性的蛋白质。这些结果表明，THBS处理通过与α2μ-球蛋白结合加剧了雄性大鼠肾脏中透明滴的形成，从而导致该蛋白质在肾皮质中积累。THBS与α2μ-球蛋白之间的相互作用似乎是这种雄性大鼠特异性蛋白质所特有的，因为THBS不与在小鼠中发现的非常相似的蛋白质相互作用。
