Enables arachidonic acid 11,12-epoxygenase activity; arachidonic acid 14,15-epoxygenase activity; and testosterone 16-alpha-hydroxylase activity. Involved in epoxygenase P450 pathway and icosanoid biosynthetic process. Located in endoplasmic reticulum membrane. Biomarker of end stage renal disease; hypertension; and mental depression. Orthologous to human CYP2C18 (cytochrome P450 family 2 subfamily C member 18). [provided by Alliance of Genome Resources, Apr 2022]