Induction of macrophage DNA synthesis by phorbol esters.

Tumor-promoting phorbol esters, such as 12-0-tetradecanoylphorbol-13-acetate (TPA), stimulate mouse peritoneal exudate macrophages to undergo DNA synthesis without added macrophage growth factor (MGF). Resident peritoneal macrophages do not respond in this manner. Plasminogen activator (PA) levels of both exudate and resident peritoneal macrophages are elevated by TPA. Thus the phorbol esters appear to mimic the action(s) of MGF and may be useful in understanding the events involved in macrophage and precursor cell growth responsiveness.