c-Fos mRNA expression after PHX and COX inhibition. c-Fos mRNA expression increases after PHX, and this increase is blocked by INDO, a COX antagonist. The inhibition is reversed by PGI2, or the NO donors, SIN-1 or SNAP. In addition, these results also provide evidence that there is interaction between NO and PGs in triggering the liver regeneration cascade (data shown as means ± SEM).