Turtle urinary bladder epithelial cell line.

1. We compared enzymatic and functional properties of a turtle bladder cell line to those of turtle bladder epithelial cells. Like the original epithelium, the cell line displays carbonic anhydrase activity and acetazolamide inhibits O2 consumption in isolated cells and acidification by cells grown in monolayers. 2. Staining with acridine orange revealed the presence of cytoplasmic orange red vesicles which could be dissipated by NH4Cl or protonophores indicating that these vesicles represent areas of low pH. 3. Addition of ATP to cells permeabilized by digitonin led to reappearance of the red granules suggesting that acidification of the vesicles is mediated by H+-ATPase.