PROSTACYCLIN AS AN INDICATOR OF PREADIPOCYTE TRANSFORMATION - STUDIESIN-VIVO BY MICRODIALYSIS AND IN-VITRO

Nontransformed (Ob1771) and polyoma virus-transformed (Ob17PY) mouse c ells from the preadipocyte Ob17 clonal line have been compared in thei r ability to release prostaglandins in vitro as well as in vivo as ass ayed by in situ microdialysis. Prostaglandin FE2, prostaglandin-2alpha and mainly prostacyclin are released in larger amounts (4- to 10-fold ) by Ob17PY cells in vitro and Ob17PY-induced tumors in vivo as compar ed to Ob1771 preadipocytes in vitro and periepididymal adipose tissue in vivo. In contrast to Ob1771 preadipocytes, none of these prostanoid s appear to be involved in the control of proliferation or differentia tion of Ob17PY cells in serum-free culture medium. However, prostacycl in, the level of which is the most affected by transformation, might b e considered as a valuable indicator of fibrosarcoma development.