ENOLASE ISOZYMES IN RENAL TUBULES AND RENAL-CELL CARCINOMA

  • 1 September 1986
    • journal article
    • research article
    • Vol. 124  (3) , 488-495
Abstract
To elucidate the localization of enolase isozymes in renal tubules and renal cell carcinoma, an immunohistochemical study and quantitative analysis by employing the enzyme immunoassay were performed. The .alpha.-enolase was localized in almost all epithelial cells of renal tubules except for loops of Henle. The .gamma.-enolase was localized in macula densa cells and epithelial cells of loops of Henle and collecting ducts of the medulla, but not in those of proximal tubules. In renal cell carcinoma, most tumor cells possessed two enolase isozymes. From these immunohistochemical findings, it is suggested that enolases are present mainly in the .alpha..alpha. form in epithelial cells of proximal tubules, in the .gamma..gamma. form in those of loops of Henle, and in the two forms and/or the .alpha..gamma. form in tumor cells of renal cell carcinoma. The levels of .gamma.-enolase in the normal cortex were 16.8 .+-. 3.7 ng/mg protein (n = 7), whereas those in renal cell carcinoma were 928 .+-. 554 ng/mg protein (n = 7), about 55-fold higher than those in the normal cortex. The serum .gamma.-enolase levels were also enhanced in 20 (49%) of 41 patients with renal cell carcinoma. Because it is generally accepted that renal cell carcinoma is derived from epithelium of proximal tubules, the expression of .gamma.-enolase has occurred during carcinogenesis.