Prostacyclin as an indicator of preadipocyte transformation: studies in vivo by microdialysis and in vitro.

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