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

Mani, O; Sorensen, M T; Sejrsen, K; Bruckmaier, R M; Albrecht, C (2009). Differential expression and localization of lipid transporters in the bovine mammary gland during the pregnancy-lactation cycle. Journal of dairy science, 92(8), pp. 3744-56. Savoy, Ill.: American Dairy Science Association 10.3168/jds.2009-2063

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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.

Item Type:

Journal Article (Original Article)


05 Veterinary Medicine > Department of Clinical Research and Veterinary Public Health (DCR-VPH) > Veterinary Physiology
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine

UniBE Contributor:

Bruckmaier, Rupert and Albrecht, Christiane




American Dairy Science Association




Factscience Import

Date Deposited:

04 Oct 2013 15:13

Last Modified:

04 May 2014 23:23

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https://boris.unibe.ch/id/eprint/32012 (FactScience: 196837)

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