title: Lipoprotein and apolipoprotein secretion by a newborn piglet intestinal cell line (IPEC-1).
abstract: The aim of these studies was to characterize the synthesis and secretion of lipoproteins and apolipoprotein B (apo B) and apo A-I by a newborn swine intestinal epithelial cell line (IPEC-1). Differentiated cells exhibited enterocytic features, including microvilli. [3H] oleic acid was taken up and incorporated into cellular lipids and secreted into the basolateral medium in lipoproteins. Total apo B and apo A-I secreted increased with oleic acid incubation. However, cellular apo B and apo A-I content did not change. Whereas undifferentiated cells synthesized and secreted only apo B-100, both apo B-100 and apo B-48 were produced by differentiated cells. The ratio of radiolabeled apo B-48 to apo B-100 in both basolateral medium and cell homogenate increased with oleic acid treatment after 24-h steady-state labeling. However, apo B mRNA editing was unchanged, indicating posttranslational regulation of this ratio. Pulse-chase radiolabeling demonstrated no major changes in cellular or basolateral medium apolipoprotein labeling kinetics with oleic acid or dexamethasone incubation. The dissociation of apo B and apo A-I mass secretion from the secretion of radiolabeled apo B and apo A-I in response to oleic acid absorption suggests the presence of an intracellular pool of apolipoprotein with a slow turnover that is mobilized for secretion in response to fatty acid uptake.
authors.affiliation: Department of Pediatrics, Arkansas Children's Hospital, University of Arkansas for Medical Sciences, Little Rock 72202, USA.
authors.forename: R
authors.initials: R
authors.lastname: Gonzalez-Vallina
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Zhan
authors.forename: H M
authors.initials: HM
authors.lastname: Berschneider
authors.forename: R M
authors.initials: RM
authors.lastname: Lee
authors.forename: N O
authors.initials: NO
authors.lastname: Davidson
authors.forename: D D
authors.initials: DD
authors.lastname: Black
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001053:Apolipoproteins / Q000378:metabolism*; D001055:Apolipoproteins B / Q000235:genetics; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D004951:Esterification; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D019301:Oleic Acid / Q000378:metabolism; D015345:Oligonucleotide Probes / Q000235:genetics; D017393:RNA Editing; D013552:Swine
chemical_list: D001053:Apolipoproteins; D001055:Apolipoproteins B; D008074:Lipoproteins; D015345:Oligonucleotide Probes; D019301:Oleic Acid