Journal of Nutrition OpenSOurce Diets- www.ResearchDiets.com

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Walzem, R. L.
Right arrow Articles by Hamilton, R. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Walzem, R. L.
Right arrow Articles by Hamilton, R. L.
(Journal of Nutrition. 1999;129:467-472.)
© 1999 The American Society for Nutritional Sciences

Supplement

Estrogen Induction of VLDLy Assembly in Egg-Laying Hens

Rosemary L. Walzem 1 , Robert J. Hansen, David L. Williamsa and Robert L. Hamiltonb ,c

Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616–8741; a Department of Pharmacological Sciences, Health Sciences Center, State University of New York at Stony Brook, Stony Brook, NY 11794–8651; and b Cardiovascular Research Institute and c Department of Anatomy, University of California, San Francisco, CA 94143–0130

The yolk of a 60-g chicken egg contains 6 g of triacylglycerols transported to the oocyte from the liver of the laying hen in apolipoprotein (apo) B–containing particles. With the onset of egg production, estrogen shifts hepatocytic lipoprotein production from generic VLDL to VLDLy (yolk targeted). These VLDLy are triacylglycerol-rich particles; they are reduced in size by one half, are resistant to lipoprotein lipase and are taken up intact by oocyte receptors. The VLDLy pathway for apoB provides sufficient energy for the caloric requirements of chick development. VLDLy size reduction occurs in spite of surplus liver triacylglycerols and is necessary for VLDL particles to pass through the granulosa basal lamina and reach the receptors located on the oocyte surface. New ultrastructural data show that some proximal tubule cells of bird kidney secrete generic VLDL, perhaps providing energy and other VLDL-associated nutrients to tissues bypassed by VLDLy. Birds are an apoB100-only species, providing a natural in vivo model with which to investigate mechanisms of apoB100 VLDL assembly. Preliminary studies of liver lipoprotein assembly intermediates isolated from the biosynthetic membranes (endoplasmic reticulum) of the laying hen are consistent with the presence of both putative first- and second-step precursor particles of VLDLy. These findings suggest that the two-step mechanism of apoB core lipidation is an ancient development in apoB biology, handed down to mammals from oviparous ancestors.

KEY WORDS: • apolipoproteinB100 • liver • kidney • ultrastructure • yolk deposition




This article has been cited by other articles:


Home page
 J. Lipid Res.Home page
M. M. W. Smolenaars, O. Madsen, K. W. Rodenburg, and D. J. Van der Horst
Molecular diversity and evolution of the large lipid transfer protein superfamily
J. Lipid Res., March 1, 2007; 48(3): 489 - 502.
[Abstract] [Full Text] [PDF]

Home page
 J. Lipid Res.Home page
A. Nilsson and R.-D. Duan
Absorption and lipoprotein transport of sphingomyelin
J. Lipid Res., January 1, 2006; 47(1): 154 - 171.
[Abstract] [Full Text] [PDF]

Home page
 J. Lipid Res.Home page
E. Boyle-Roden and R. L. Walzem
Integral apolipoproteins increase surface-located triacylglycerol in intact native apoB-100-containing lipoproteins
J. Lipid Res., August 1, 2005; 46(8): 1624 - 1632.
[Abstract] [Full Text] [PDF]


Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]