Electrolyte homeostasis in urothelial neoplasia: the effects of amiloride.
OBJECTIVE
To investigate the effect of amiloride preincubation on the intracellular electrolyte levels in neoplastic and non-neoplastic urothelium.


METHODS
Samples of papillary transitional cell carcinomas (grades 1 and 2) and non-neoplastic human urothelium were either frozen immediately or after pre-incubation with Krebs saline alone or with Krebs saline containing amiloride. The frozen samples were planed in a cryo-ultramicrotome and then examined by low temperature scanning electron microscopy. Intracellular electrolyte levels were measured using X-ray microanalysis.


RESULTS
In the cells frozen immediately the ratios K+/Na+, K+/P and K+/Cl- were significantly increased in neoplastic compared with non-neoplastic urothelial cells (P < 0.001). This difference was also found in the cells pre-incubated with Krebs saline alone but was not present in the cells pre-incubated with amiloride.


CONCLUSIONS
These results were consistent with the concept that activation of the amiloride-sensitive Na+/H+ membrane exchanger is a primary event in neoplasia.
Cartman
M L
ML
Division of Biological Sciences, IEBS, Lancaster University, UK.
Morris
J A
JA
Huddart
H
H
Staff
W G
WG
D000368:Aged; D000369:Aged, 80 and over; D000584:Amiloride / Q000378:metabolism / Q000627:therapeutic use*; D002295:Carcinoma, Transitional Cell / Q000378:metabolism*; D002713:Chlorine / Q000378:metabolism*; D004577:Electron Probe Microanalysis; D005260:Female; D006487:Hemostasis; D006801:Humans; D017136:Ion Transport; D008297:Male; D008875:Middle Aged; D010758:Phosphorus / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D014571:Urologic Neoplasms / Q000188:drug therapy / Q000378:metabolism*
D010758:Phosphorus; D002713:Chlorine; D000584:Amiloride; D012964:Sodium; D011188:Potassium