Urothelial function reconsidered: A role in urinary protein secretion

Fang Ming Deng, Mingxiao Ding, Robert M. Lavker, Tung Tien Sun*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Mammalian bladder epithelium functions as an effective permeability barrier. We demonstrate here that this epithelium can also function as a secretory tissue directly involved in modifying urinary protein composition. Our data indicate that normal bovine urothelium synthesizes, as its major differentiation products, two well-known proteases: Tissue-type plasminogen activator and urokinase, as well as a serine protease inhibitor, PP5. Moreover, we demonstrate that the urothelium secretes these proteins in a polarized fashion into the urine via a cAMP- and calcium-regulated pathway. Urinary plasminogen activators of ruminants are therefore urothelium derived rather then kidney derived as in some other species; this heterogeneity may have evolved in response to different physiological or dietary factors. In conjunction with our recent finding that transgenic mouse urothelium can secrete ectopically expressed human growth hormone into the urine, our data establish that normal mammalian urothelium can function not only as a permeability barrier but also as a secretor of urinary proteins that can play physiological or pathological roles in the urinary tract.

Original languageEnglish (US)
Pages (from-to)154-159
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
StatePublished - Jan 2 2001

ASJC Scopus subject areas

  • General


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