title: Hepatic Retinyl Ester Hydrolases and the Mobilization of Retinyl Ester Stores.
abstract: For mammals, vitamin A (retinol and metabolites) is an essential micronutrient that is required for the maintenance of life. Mammals cannot synthesize vitamin A but have to obtain it from their diet. Resorbed dietary vitamin A is stored in large quantities in the form of retinyl esters (REs) in cytosolic lipid droplets of cells to ensure a constant supply of the body. The largest quantities of REs are stored in the liver, comprising around 80% of the body's total vitamin A content. These hepatic vitamin A stores are known to be mobilized under times of insufficient dietary vitamin A intake but also under pathological conditions such as chronic alcohol consumption and different forms of liver diseases. The mobilization of REs requires the activity of RE hydrolases. It is astounding that despite their physiological significance little is known about their identities as well as about factors or stimuli which lead to their activation and consequently to the mobilization of hepatic RE stores. In this review, we focus on the recent advances for the understanding of hepatic RE hydrolases and discuss pathological conditions which lead to the mobilization of hepatic RE stores.
authors.affiliation: Institute of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria. lgrumet@gmail.com.
authors.forename: Lukas
authors.initials: L
authors.lastname: Grumet
authors.affiliation: Institute of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria. ulrike.taschler@uni-graz.at.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Taschler
authors.affiliation: Institute of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria. achim.lass@uni-graz.at.
authors.forename: Achim
authors.initials: A
authors.lastname: Lass
mesh_terms: D000437:Alcoholism / Q000503:physiopathology; D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D008107:Liver Diseases / Q000503:physiopathology; D014801:Vitamin A / Q000008:administration & dosage / Q000378:metabolism
chemical_list: D014801:Vitamin A; D002265:Carboxylic Ester Hydrolases; C022523:retinyl esterase
keywords: hepatic stellate cells; hepatocyte; lipid droplet; liver; mobilization; retinyl ester hydrolase