title: Circadian regulators of intestinal lipid absorption.
abstract: Among all the metabolites present in the plasma, lipids, mainly triacylglycerol and diacylglycerol, show extensive circadian rhythms. These lipids are transported in the plasma as part of lipoproteins. Lipoproteins are synthesized primarily in the liver and intestine and their production exhibits circadian rhythmicity. Studies have shown that various proteins involved in lipid absorption and lipoprotein biosynthesis show circadian expression. Further, intestinal epithelial cells express circadian clock genes and these genes might control circadian expression of different proteins involved in intestinal lipid absorption. Intestinal circadian clock genes are synchronized by signals emanating from the suprachiasmatic nuclei that constitute a master clock and from signals coming from other environmental factors, such as food availability. Disruptions in central clock, as happens due to disruptions in the sleep/wake cycle, affect intestinal function. Similarly, irregularities in temporal food intake affect intestinal function. These changes predispose individuals to various metabolic disorders, such as metabolic syndrome, obesity, diabetes, and atherosclerosis. Here, we summarize how circadian rhythms regulate microsomal triglyceride transfer protein, apoAIV, and nocturnin to affect diurnal regulation of lipid absorption.
authors: Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203; and Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY 11209.
authors: M Mahmood
authors: MM
authors: Hussain
authors: Departments of Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203; and Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY 11209.
authors: Xiaoyue
authors: X
authors: Pan
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics; D005502:Food; D005786:Gene Expression Regulation / Q000528:radiation effects; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D050356:Lipid Metabolism / Q000502:physiology* / Q000528:radiation effects
keywords: MTP; apoAIV; clock genes; lipoproteins; nocturnin; rhythms; triglycerides