Linked Life Data

7964272

Source:http://linkedlifedata.com/resource/pubmed/id/7964272

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-12-7
pubmed:abstractText
To investigate an involvement of endogenous opioids in the regulation of circannual changes in reproductive activity, effects of the opioid antagonist naloxone on the concentration of immunoreactive and bioactive luteinizing hormone (LH) in plasma were measured in mares during the anovulatory season. Naloxone (0.5 mg/kg i.v.) caused a significant increase (P < 0.05) in immunoreactive as well as bioactive LH concentration in plasma. The amplitude of the increase in LH concentrations measured with an in vitro bioassay was more pronounced than the amplitude of the increase in LH secretion determined by radioimmunoassay. This indicates that although in seasonal anovulatory mares the bioactivity of LH in plasma is low, highly bioactive LH is present in the anterior pituitary and can be released by naloxone. The LH response to naloxone did not depend on the degree of ovarian follicular activity. It can be concluded that a tonic opioid inhibition of LH release is present in mares during at least part of the anovulatory season and that endogenous opioids seem to be involved in the regulation of seasonal reproductive activity in the horse. In contrast to the situation during the breeding season, the opioid systems regulating LH release are activated independently of luteal progesterone.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-0795
pubmed:author
pubmed:issnType
Print
pubmed:volume
142
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
139-44
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Effects of the opioid antagonist naloxone on release of luteinizing hormone in mares during the anovulatory season.
pubmed:affiliation
Institut für Reproduktionsmedizin, Tierärztliche Hochschule Hannover, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't