Lecithin:retinol acyltransferase expression is regulated by dietary vitamin A and exogenous retinoic acid in the lung of adult rats.
Lecithin:retinol acyltransferase (LRAT), a retinol esterifying enzyme, plays a major role in the metabolism and storage of vitamin A in several animal tissues. Groups of vitamin A (VA)-adequate (control) and VA-deficient rats were treated with vehicle or 5 mg of all-trans-retinoic acid (RA); an additional group of VA-deficient rats were fed 100 microg of RA. In control rats, lung LRAT mRNA and LRAT specific activity were approximately 50% of the levels expressed in the liver. In the lung of VA-deficient rats, LRAT mRNA and specific activity levels were <10% of those in the control group. Treatment of VA-deficient rats with 100 microg RA increased lung LRAT mRNA (P < 0.005) and specific activity (P < 0.0001), and treatment with 5 mg of RA increased LRAT mRNA level and specific activity more than approximately 15- and 6-fold above those in control lung, respectively (both P < or = 0.001). The lung tissue of VA-adequate rats contained retinyl ester (approximately 3 nmol/g tissue), whereas none was detected in the lung tissue of VA-deficient rats. These results show that LRAT expression and vitamin A storage are regulated by vitamin A status and by treatment with all-trans-RA in the adult lung. These results suggest that the regulated storage of vitamin A may be important for maintaining the integrity and physiologic functions of the lung.
Zolfaghari
Reza
R
Department of Nutrition, The Pennsylvania State University, University Park, PA 16802, USA.
Ross
A Catharine
AC
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008168:Lung / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011917:Rats, Inbred Lew; D014212:Tretinoin / Q000008:administration & dosage*; D014801:Vitamin A / Q000008:administration & dosage / Q000378:metabolism*; D014802:Vitamin A Deficiency / Q000378:metabolism*
D012333:RNA, Messenger; D014801:Vitamin A; D014212:Tretinoin; D000217:Acyltransferases; C056942:lecithin-retinol acyltransferase