title: Triacylglyceride physiology in the short-finned eel, Anguilla australis—changes throughout early oogenesis.
abstract: During certain stages in an animal's life cycle, energy requirements may exceed energy intake from the diet. The spawning migration of temperate eels is a textbook example of negative energy balance, forcing these fish to rely on stored fats (triacylglycerides) to provide their muscles with energy for swimming and their growing oocytes with the nutrients needed to develop and support healthy offspring. We predicted broad implications of this great need for endogenous triacylglycerides in terms of their packaging, transport, and ovarian uptake. To test this, serum lipid concentrations and transcript abundances of intestinal and hepatic triacylglyceride packagers and ovarian triacylglyceride modifiers and receivers were investigated throughout previtellogenesis (feeding phase) and into early vitellogenesis (fasting phase) in short-finned eels. A switch from exogenous to endogenous triacylglyceride packaging was seen as the liver upregulated transcript levels of apolipoprotein B and microsomal triacylglyceride transport protein and downregulated those of apolipoprotein E and lipoprotein lipase. In the intestine, the reverse response was observed. Furthermore, ovarian transcript abundances of triacylglyceride modifiers and receivers increased (apolipoprotein E, lipoprotein lipase, and vitellogenin receptor), indicative of increased triacylglyceride uptake during previtellogenesis. We propose that increased hepatic apolipoprotein B production is a conserved vertebrate response to prolonged periods of negative energy balance.
authors: Department of Zoology, University of Otago, Dunedin, New Zealand; and erin.damsteegt@otago.ac.nz.
authors: Erin L
authors: http://orcid.org/0000-0001-8972-9313
authors: EL
authors: Damsteegt
authors: Department of Zoology, University of Otago, Dunedin, New Zealand; and.
authors: Ali
authors: A
authors: Falahatimarvast
authors: Department of Biochemistry, School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors: Sally P A
authors: SP
authors: McCormick
authors: Department of Zoology, University of Otago, Dunedin, New Zealand; and.
authors: P Mark
authors: PM
authors: Lokman
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001055:Apolipoproteins B / Q000235:genetics / Q000378:metabolism; D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004524:Eels / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism; D005260:Female; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D007413:Intestinal Mucosa / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism*; D009866:Oogenesis; D010053:Ovary / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*; D014818:Vitellogenesis
chemical_list: D001055:Apolipoproteins B; D001057:Apolipoproteins E; D002352:Carrier Proteins; D029941:Fish Proteins; D012333:RNA, Messenger; D014280:Triglycerides; C106092:microsomal triglyceride transfer protein; D008071:Lipoprotein Lipase
keywords: migration; neutral lipids; oil droplets; previtellogenesis; starvation