Vitamin A absorption and storage operate within cellular biology through a fat-soluble lipid transport mechanism involving esterification to form retinyl esters in intestinal mucosal cells for incorporation into chylomicrons, which deliver the nutrient to the liver for hepatic storage as palmitic acid derivatives. The core theoretical distinction between its physiological functions relies on metabolic interconversion: visual acuity is mediated by aldehyde forms (retinal) utilized within rhodopsin photopigments in retinal cells, while gene regulation and protein synthesis are driven by acidic forms acting via nuclear receptor pathways to modulate DNA transcription and cellular differentiation.
This concept covers the three chemical forms of vitamin A (retinol, retinal, retinoic acid) and their distinct biological roles, with particular emphasis on how the isomerization of 11-cis retinal up…