Fatty aldehydes may be produced during decomposition of fatty acid hydroperoxides following a peroxidation attack. These compounds, which are thought to play a role in the regulation of thyroid function, were recently shown to be formed by the attack of reactive iodine on the vinyl ether group of PE plasmalogen . In some bacteria, aldehyde analogs of cyclopropane fatty acids were described. Several isoprenoid aldehydes are important in insect biology as pheromones and in botany as volatile odorous substances. Retinal exist in two forms, a cis and a trans isomer.
Retinol is stocked in retina mainly in an acylated form.