Document Detail


Evolution of the mammary capillary network and carbonic anhydrase activity throughout lactation and during somatotropin treatment in goats.
MedLine Citation:
PMID:  20500913     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
During the normal course of lactation, mammary metabolic activity and blood flow are closely correlated. Six lactating goats were used in this experiment to test the hypothesis that the capillary network and the capillary enzyme, carbonic anhydrase (CA; EC 4.2.1.1) are important regulatory factors involved in the coordination of mammary blood flow (MBF) and metabolic activity. Milk vein blood velocity was determined as a measure of MBF, and fine needle mammary biopsies were obtained at different time points during lactation and by the end of a 14-d bovine somatotropin (BST) treatment initiated 3 months post partum. In mammary sections, CA activity was determined histochemically and alveolar and capillary structures by image analyses upon azure blue staining. In early lactation, alveoli were large and surrounded by many small capillaries with high CA activity. As lactation progressed, capillaries almost tripled in size, whereas number of capillaries surrounding each alveolus decreased by 1/3, and CA activity more than halved. BST treatment did not affect capillary traits but increased number of alveoli in mammary sections, and BST thus appeared to be targeted mostly towards the mammary epithelial cell. Milk vein blood velocity decreased over the course of lactation, when capillary area markedly increased, suggesting that control of mammary blood perfusion is not at the level of the capillary itself, but at pre- or post-capillary sites. We suggest that the observed changes in capillary diameter and CA activity with progressing lactation contributes to reduce efficiency of nutrient and waste product exchange across the capillary-mammary epithelial cell barrier, and this could be an important factor in regulation of mammary (epithelial cell) metabolic activity and lactation performance.
Authors:
Mette O Nielsen; Katarina Cvek; Kristina Dahlborn
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-05-25
Journal Detail:
Title:  The Journal of dairy research     Volume:  77     ISSN:  1469-7629     ISO Abbreviation:  J. Dairy Res.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-06-25     Completed Date:  2010-10-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985125R     Medline TA:  J Dairy Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  368-75     Citation Subset:  IM    
Affiliation:
Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Grønnegaardsvej 7, DK-1870 Frederiksberg C. mon@life.ku.dk
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Flow Velocity / veterinary
Capillaries / physiology
Carbonic Anhydrases / metabolism,  physiology*
Cattle
Female
Goats / physiology
Growth Hormone / pharmacology
Lactation / drug effects,  metabolism,  physiology*
Mammary Glands, Animal / blood supply*,  drug effects,  enzymology,  physiology
Milk / secretion
Chemical
Reg. No./Substance:
9002-72-6/Growth Hormone; EC 4.2.1.1/Carbonic Anhydrases

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