JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Dairy Sci. 2009. 92:3744-3756. doi:10.3168/jds.2009-2063
© 2009 American Dairy Science Association ®
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow __Color Figure 1
Right arrow Interpretive Summary
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 Google Scholar
Google Scholar
Right arrow Articles by Mani, O.
Right arrow Articles by Albrecht, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mani, O.
Right arrow Articles by Albrecht, C.

Differential expression and localization of lipid transporters in the bovine mammary gland during the pregnancy-lactation cycle

O. Mani*, M. T. Sorensen{dagger}, K. Sejrsen{dagger}, R. M. Bruckmaier{ddagger} and C. Albrecht*,1

* Institute of Biochemistry and Molecular Medicine, University of Bern, CH-3012 Bern, Switzerland
{dagger} Department of Animal Health, Welfare and Nutrition, Aarhus University, DK-8830, Tjele, Denmark
{ddagger} Veterinary Physiology, Vetsuisse Faculty, University of Bern, CH-3001 Bern, Switzerland

1 Corresponding author: christiane.albrecht{at}mci.unibe.ch

The transport of lipids across mammary gland epithelial cells (MEC) determines milk lipid content and composition. We investigated the expression of lipid transporters and their regulators in comparison to blood metabolites during lactation and dry period (DP) in dairy cows. Repeated mammary gland biopsies and blood samples were taken from 10 animals at 7 stages of the pregnancy-lactation cycle. Expression levels of the specific mRNAs were determined by quantitative reverse transcription-PCR, whereas ABCA1 was localized by immunohistochemistry. Blood serum metabolites were determined by common enzymatic chemistries. Elevated mRNA profiles of ABCA1 and ABCA7 were found during DP as compared with lactation and were inversely associated with blood cholesterol levels. Elevated levels of ABCG2, NPC1, SREBP1, SREBP2, LXR{alpha}, and PPAR{gamma} were found postpartum, whereas ABCG1 did not differ between the functional stages of the mammary gland. The ABCA1 protein was localized in MEC and showed differential activity between DP and lactation suggesting a role of ABCA1 in the removal of excess cellular cholesterol from MEC during the DP. The expression profiles of ABCA7 and NPC1 may reflect a role of these transporters in the clearance of apoptotic cells and the intracellular redistribution of cholesterol, respectively. Regulation of lipid transporters in the mammary gland is partially associated with transcription factors that control lipid homeostasis.

Key Words: ATP-binding cassette transporter • cholesterol • lipid homeostasis • mammary gland






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by the American Dairy Science Association ®.