VITAMIN-A STORAGE AND PEROXISOMES IN RETINAL-PIGMENT EPITHELIUM AND LIVER

  • 1 January 1977
    • journal article
    • research article
    • Vol. 16  (12) , 1110-1117
Abstract
Retinas and livers were studied with histochemical methods for catalase combined with light microscopy and EM, following i.m. injections of C57 black mice with retinyl acetate or retinyl palmitate in total doses of 0.9-6.7 .times. 106 IU/kg body wt. There were clear, dose-related increases in numbers and sizes of vitamin A-storing lipid droplets in stellate cells of the liver. More conservative increases in similar lipid droplets occurred in the pigment epithelium but not in other cells of the retina. Such lipid droplets may represent physiological sites of vitamin A storage which are important for maintenance of photoreceptor cells by the retinal pigment epithelium. No changes in lipids of the retina or liver were observed in mice injected with retinoic acid or with peanut oil. Peroxisomes containing catalase and the putative vitamin A-storing lipid droplets were distributed along basal and lateral cell surfaces of the pigment epithelium where receptors for plasma retinol-binding protein were reported. Peroxisomes may play a role in reactions related to esterification and sequestering of vitamin A.