Lipid mediators & sterols
Sterol-derived hormones, bile acids and oxygenated polyunsaturated-fatty-acid mediators.
Lipid mediators are often made on demand from membrane-derived precursors. Arachidonate can be oxygenated through cyclooxygenase, lipoxygenase and cytochrome-P450 branches, producing families with different receptors and lifetimes.
Specialized pro-resolving mediators arise through staged oxygenation of omega-3 and related polyunsaturated fatty acids. Their pathway placement describes biosynthetic chemistry; it does not by itself establish concentration, cell source or effect in a specific disease state.
Steroid and bile-acid pathways begin with cholesterol but diverge through different organelles, tissues and conjugation steps. The map uses shared ancestry as a junction while preserving each reaction sequence.
Ideas to carry into the map
- On-demand synthesis begins from defined lipid precursors.
- Oxygenase branches create distinct mediator families.
- Pathway topology alone does not establish a biological effect.
Pathways in this field note
Interconversion of cholesterol-derived steroid frameworks across mitochondrial, endoplasmic-reticulum and cytosolic reactions.
Synthesis, conjugation, transport and recycling of amphipathic cholesterol metabolites.
Liberation and oxygenation of arachidonate into prostanoid, leukotriene and related mediator branches.
Enzymatic routes to lipoxins, resolvins, protectins and maresins from polyunsaturated fatty acids.