Ingested fat and satiety.
Apolipoprotein A-IV (apo A-IV) is secreted by the intestine associated with chylomicron. Intestinal apo A-IV synthesis is stimulated by fat absorption, probably mediated by chylomicron formation. The stimulation of apo A-IV synthesis in the jejunum and ileum is attenuated by intravenous leptin infusion. Intestinal apo A-IV synthesis is also stimulated by a factor from the ileum, probably peptide tyrosine-tyrosine (PYY), which has been demonstrated to affect satiety. Apo A-IV has been proposed to physiologically control food intake, and this inhibitory effect is centrally mediated. Recently, apo A-IV was demonstrated in the hypothalamus. The hypothalamic apo A-IV level was reduced by food deprivation and restored by lipid feeding. Intracerebroventricular administration of apo A-IV antiserum stimulated feeding and decreased the hypothalamic apo A-IV mRNA level, implying that feeding is normally limited by endogenous apo A-IV. Central administration of neuropeptide Y (NPY) significantly increased hypothalamic apo A-IV mRNA levels in a dose-dependent manner. The stimulation of intestinal synthesis and secretion of apo A-IV by lipid absorption are rapid; thus, apo A-IV is capable of short-term regulation of food intake. Evidence also suggests apo A-IV's involvement in long-term regulation of food intake and bodyweight. The chronic ingestion of high fat blunts the intestinal apo A-IV response to lipid feeding and may therefore explain why chronic intake of high fat predisposes animals and humans to obesity.
Tso
Patrick
P
Department of Pathology, University of Cincinnati Medical Center, 231 Albert Sabin Way (ML 0529), Cincinnati, OH 45267-0529, USA. tsopp@email.uc.edu
Liu
Min
M
D000818:Animals; D001053:Apolipoproteins / Q000378:metabolism; D001054:Apolipoproteins A / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D004041:Dietary Fats / Q000494:pharmacology*; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D019894:Peptide YY / Q000502:physiology; D012528:Satiety Response / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
D001053:Apolipoproteins; D001054:Apolipoproteins A; D004041:Dietary Fats; C022205:apolipoprotein A-IV; D019894:Peptide YY