Electrolyte Levels in Neoplastic and Nonneoplastic Human Urothelium After Ouabain Treatment: X-Ray Microanalysis of Bulk Hydrated Samples

Abstract

Samples of neoplastic and nonneoplastic human urothelium were immediately frozen, incubated in Krebs' saline and then frozen, or incubated in 10⁻⁵ mol/L ouabain in Krebs' saline and then frozen. The frozen specimens were then planed in a cryoultramicrotome and examined by low-temperature scanning electron microscopy. X-Ray microanalysis was performed on the superficial urothelial cells. Neoplastic cells immediately frozen and those incubated in Krebs' saline had significantly higher K⁺/Na⁺, K⁺/P, and K⁺/Cl⁻ ratios and lower Na⁺/P and Cl⁻/P ratios than nonneoplastic cells. Incubation in ouabain led to a fall in the K⁺/Na⁺, K⁺/P, and K⁺/Cl⁻ ratios and a rise in the Na⁺/P and Na⁺/Cl⁻ ratios in both neoplastic and nonneoplastic cells and effectively nullified the difference between them. These results are consistent with the concept that in neoplasia a primary event is stimulation of Na⁺/H⁺ exchange, which leads to secondary stimulation of the ouabain-sensitive Na⁺/K⁺ ATPase pump.

Key Words:

• low-temperature scanning electron microscopy
• ouabain
• quantitative X-ray microanalysis
• urothelial tumors