ELECTROLYTE LEVELS IN NEOPLASTIC AND NONNEOPLASTIC HUMAN UROTHELIUM AFTER OUABAIN TREATMENT - X-RAY-MICROANALYSIS OF BULK HYDRATED SAMPLES

Samples of neoplastic and nonneoplastic human urothelium were immediat ely frozen, incubated in Krebs' saline and then frozen, or incubated i n 10(-5) mol/L ouabain in Krebs' saline and then frozen. The frozen sp ecimens were then planed in a cryoultramicrotome and examined by low-t emperature scanning electron microscopy. X-Ray microanalysis was perfo rmed 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 i n both neoplastic and nonneoplastic cells and effectively nullified th e difference between them. These results are consistent with the conce pt 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.