The role of the Golgi apparatus during terminal differentiation of mouse urothelial surface cells

The development of the Golgi apparatus in the surface cells of mouse urinar y bladder during embryonic development was investigated by electronmicrosco pic cytochemistry. The distributions of NADPase and TPPase activities were studied in the urinary bladder during day 15 to day IX of gestation. At the early embryonic stage, the products of the NADPase and TPPase reactions we re visible exclusively in 1 to 2 medial and/or trans Golgi saccules. The st rongest increment of NADPase and TPPase positive Golgi cisternae was detect ed at day 17 when the activity of the urothelial cells was very prominent. Al this age, NADPase activity was detected also in lysosomes and on the api cal surface of the urothelial cells. The highest distribution pattern of NA DPase and TPPase activities observed at this stage rapidly decreases at day 18 of fetal life. The results suggest that the organization of the Golgi a pparatus reflected the intensity of the processes occuring in the urothelia l cells during gestation.