Catalyzes the reduction of prostaglandin-ethanolamide H(2) (prostamide H(2)) to prostamide F(2alpha) with NADPH as proton donor. Also able to reduce prostaglandin H(2) to prostaglandin F(2alpha). [thioredoxin]-dithiol + prostaglandin H2 = [thioredoxin]-disulfide + prostaglandin F2alpha [thioredoxin]-disulfide + prostamide F2alpha = [thioredoxin]-dithiol + prostamide H2 Mainly present in brain and spinal cord. In spinal cord, present in the superficial layer of the dorsal horn, in motor neurons of the ventral horn and in glia of the white matter of the spinal cord. In brain, expressed preferentially in the white matter bundles of the entire CNS of adult with less marked expression in neuronal cell bodies. Colocalizes with MBP in myelin sheaths but not in axons. Localizes to myelin sheaths (at protein level). Belongs to the peroxiredoxin-like PRXL2 family. Prostamide/prostaglandin F synthase subfamily.