Table 1.

Concentrations of plasminogen activators in bovine urine, urothelia-conditioned media, and urothelial cells, as calculated from the zymography data

	Urine, μg/liter	Conditioned media, μg/liter*		Urothelium, μg/mg cellular protein
		Organ culture	Cell culture	In vivo	Cell culture
uPA	500†	100	150	10	8
tPA	250	50	200	5	15

^*Because bovine bladder has an average surface area of ≅200 cm², in contact with ≅5 liters of urine per day, these numbers were adjusted to be equivalent to media exposed to cultured urothelial cells at 37°C for 24 h, at a ratio of 25 ml/cm² surface area of cells. 

^† Similar concentrations of uPA were found in human (100–1,000 μg/liter) (ref. 38 and data not shown) and mouse urine (≅1,800 μg/liter) (49).