Linked Life Data

21047946

Source:http://linkedlifedata.com/resource/pubmed/id/21047946

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2010-11-24
pubmed:abstractText
During lactation, calcium is mobilized from the maternal skeleton to supply the breast for milk production. This results in rapid but fully reversible bone loss. Prior studies have suggested that PTHrP, secreted from the breast, and estrogen deficiency, due to suckling-induced central hypogonadism, combine to trigger bone resorption. To determine whether this combination was sufficient to explain bone loss during lactation, we raised PTHrP levels and decreased levels of estrogens in nulliparous mice. PTHrP was infused via osmotic minipumps and estrogens were decreased either by using leuprolide, a long-acting GnRH agonist, or by surgical ovariectomy (OVX). Bone mineral density declined by 23.2 ± 1.3% in the spine and 16.8 ± 1.9% in the femur over 10 d of lactation. This was accompanied by changes in trabecular architecture and an increase in both osteoblast and osteoclast numbers. OVX and PTHrP infusion both induced a modest decline in bone mineral density over 10 d, but leuprolide treatment did not. The combination of OVX and PTHrP was more effective than either treatment alone, but there was no interaction between PTHrP and leuprolide. None of the treatments reproduced the same degree of bone loss caused by lactation. However, both forms of estrogen deficiency led to an increase in osteoclasts, whereas infusion of PTHrP increased both osteoblasts and osteoclasts. Therefore, although the combination of PTHrP and estrogen deficiency contributes to bone loss, it is insufficient to reproduce the full response of the skeleton to lactation, suggesting that other factors also regulate bone metabolism during this period.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1945-7170
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
151
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5591-601
pubmed:dateRevised
2011-4-15
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Increased PTHrP and decreased estrogens alter bone turnover but do not reproduce the full effects of lactation on the skeleton.
pubmed:affiliation
Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8020, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural