[Regulation of cell growth by prostaglandins].
Prostaglandins (PGs) are known to be widely distributed in the living body, and have a broad spectrum of biological effects on almost all the systems of the body. In this paper, we summarized the regulation of cell growth by PGs. Among several PGs, both PG-F2 alpha and thromboxanes stimulate the cell growth, while AGE, E2, D2 and A2 inhibit the cell growth. The role of PGF2 alpha on the cell growth may be the initiation of DNA replication. PGE1 and E2 stimulate the formation of cyclic AMP in a number of cells. Cyclic AMP plays a role in the regulation of cell growth. Therefore, the inhibitory effects of PGE on cell growth seem to be done by influencing cyclic AMP level. It is possible that PGE produced by tumor cells in vivo will suppress immune systems of the host animals. But more precise studies are required to understand exactly the self-regulation of cell growth by PGs and the mechanism of stimulatory or inhibitory effects of PGs.