Heavy Metal Nephropathy Induced by Tributyltin Oxide

Tributyltin oxide (TBTO) nephropathy was induced by painting it on the back skin of guinea pigs. Eighteen guinea pigs were divided into three groups; Group A: 6 guinea pigs treated by 10 mg/kg/day of TBTO, Group B : 6 treated by 40 mg/kg/day, Group C: 6 as controls. Histologic findings of the kidney, excretion of electrolytes and amino acids in urine, serum eiectrolytes and amino acids, and protein excretion in urine were investigated. The results were as follows. 1. On light microscopic studies, tubular changes in Group A & B were characterized by swelling, degeneration and destruction of tubular epithelium. No glomerular lesion was found. 2. Urinary protein in Group A revealed the pattern of tubular proteinuria at day 80, by polyacrylamide gel electrophoresis procedure with sodium dodecyl sulfate. 3. In Group A, urinary excretion of sodium, chloride, inorganic phosphate, and a fair number of amino acids, especially proline and glycine, were increased at day 50. These urinary losses were occurred by the damage of proximal tubules which was caused by treatment of TBTO. In Group B, the pattern of amino aciduria was almost the same as in Group A. 4. In Group A, the serum concentrations of inorganic phosphate and some amino acids were lower than in controls because of their urinary losses. These data support the conclusion that the tubular damage, mainly proximal tubules, was induced by TBTO treatment.