Document Detail

Concurrent pregnancy retards mammary involution: effects on apoptosis and proliferation of the mammary epithelium after forced weaning of mice.
MedLine Citation:
PMID:  11967212     Owner:  NLM     Status:  MEDLINE    
The effect of pregnancy on postweaning mammary gland involution was investigated in mice. On the third day after forced weaning at Lactation Day 10, the apoptotic index was 56% lower in mammary tissue of mice that were pregnant at the time of weaning than in nonpregnant mice. Conversely, the bromodeoxyuridine-labeling index was increased sevenfold in pregnant mice compared to nonpregnant controls (3.5% vs. 0.5%, respectively). Structure of mammary alveoli was largely maintained in postweaning pregnant mice. The effect of pregnancy on three specific mammary epithelial cell survival pathways was also examined. First, pregnancy blocked the loss of Stat5a phosphorylation during involution. Significantly, loss of Stat5a phosphorylation during involution was not correlated with loss of Stat5a nuclear localization. Second, pregnancy maintained nuclear-localized progesterone receptor during lactation. Third, pregnancy was associated with increased expression of bfl-1 during involution but had little effect on the expression of other bcl-2 family members. The data indicate that pregnancy inhibits mammary cell apoptosis after weaning while permitting proliferation of the mammary epithelium, and they support the hypothesis that Stat5a and progesterone-signaling pathways act in concert to mediate this effect.
Anthony V Capuco; Minglin Li; Ezhou Long; Shuxun Ren; Kathleen S Hruska; Kristel Schorr; Priscilla A Furth
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biology of reproduction     Volume:  66     ISSN:  0006-3363     ISO Abbreviation:  Biol. Reprod.     Publication Date:  2002 May 
Date Detail:
Created Date:  2002-04-22     Completed Date:  2002-09-10     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0207224     Medline TA:  Biol Reprod     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1471-6     Citation Subset:  IM    
Gene Evaluation and Mapping Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
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MeSH Terms
Antimetabolites / diagnostic use
Apoptosis / physiology*
Blotting, Western
Bromodeoxyuridine / diagnostic use
Cell Division / physiology
DNA-Binding Proteins / metabolism
Epithelium / growth & development
Mammary Glands, Animal / chemistry,  physiology*
Milk Proteins*
Nuclease Protection Assays
Pregnancy, Animal / physiology*
Progesterone / physiology
Prolactin / physiology
Receptors, Progesterone / physiology
STAT5 Transcription Factor
Trans-Activators / metabolism
Grant Support
Reg. No./Substance:
0/Antimetabolites; 0/DNA-Binding Proteins; 0/Milk Proteins; 0/Receptors, Progesterone; 0/STAT5 Transcription Factor; 0/Stat5a protein, mouse; 0/Trans-Activators; 57-83-0/Progesterone; 59-14-3/Bromodeoxyuridine; 9002-62-4/Prolactin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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