Document Detail

Effect of exercise on the rat mammary gland: implications for carcinogenesis.
MedLine Citation:
PMID:  12028135     Owner:  NLM     Status:  MEDLINE    
Physical activity has been associated with decreased risk for developing breast cancer yet to date, the mechanism remains unknown. The purpose of this investigation was to evaluate the effects of moderate exercise training on the normal mammary gland in an attempt to identify alterations or differences that might be associated with tumour inhibition. A total of 170 female Sprague-Dawley rats were randomized to baseline (n=10), exercise (EX; n=80), or sham-exercise groups (SHAM; n=80). Treadmill training (20-25 m min-1, 15% grade, 30 min day-1, 5 days week-1) was started at 28 days of age (DOA). Animals were killed at 28, 42, 56, 70 and 84 DOA. Mammary glands were evaluated by histology and immunohistochemistry. Terminal end buds (TEB), structures susceptible to carcinogenesis, were counted. Sexual maturation, estradiol and progesterone, and organ and muscle weights were also evaluated. No differences in growth, sexual maturation, or steroid hormones were observed in response to training. No difference in the number of TEBs was observed at any timepoint between EX and SHAM. Proliferation was significantly increased at 56 DOA and tended to be increased at 42 and 70 DOA in the EX animals whereas cell death was significantly increased at 70 DOA and tended to be increased at 84 DOA in the EX animals. These data suggest no difference in the number of carcinogen-susceptible structures as a result of moderate exercise. The changes in cell proliferation and apoptosis with exercise training suggest altered cell turnover that will necessitate future study particularly with relevance to carcinogenesis.
K C Westerlind; H L McCarty; K J Gibson; R Strange
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Acta physiologica Scandinavica     Volume:  175     ISSN:  0001-6772     ISO Abbreviation:  Acta Physiol. Scand.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-05-24     Completed Date:  2002-09-16     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370362     Medline TA:  Acta Physiol Scand     Country:  England    
Other Details:
Languages:  eng     Pagination:  147-56     Citation Subset:  IM    
AMC Cancer Research Center, Denver, CO 80214, USA.
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MeSH Terms
Body Weight
Cell Division
Cell Transformation, Neoplastic*
Estradiol / blood
Mammary Glands, Animal / cytology*,  growth & development*,  pathology
Organ Size
Physical Conditioning, Animal / physiology*
Progesterone / blood
Rats, Sprague-Dawley
Sexual Maturation
Grant Support
Reg. No./Substance:
50-28-2/Estradiol; 57-83-0/Progesterone

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

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