Linked Life Data

6617580

Source:http://linkedlifedata.com/resource/pubmed/id/6617580

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1983-11-23
pubmed:abstractText
The short loop feedback effect of PRL was studied in young (4-5 months of age) and old (24-26 months of age) ovariectomized rats after a single iv injection of bovine PRL (bPRL, 500 micrograms/100 g BW) or BSA (500 micrograms/100 g BW). Blood samples were collected via intraatrial cannula every 20 min for assay of PRL. Plasma PRL levels in both young and old ovariectomized rats were pulsatile in nature, and showed approximately one PRL pulse per hour. The magnitude of the PRL peaks and concentrations of plasma PRL, but not the number of PRL peaks, were significantly greater in the old than in the young rats. The effect of bPRL on in situ PRL release was studied after verifying that bPRL does not cross-react with rat PRL RIA, but does significantly increase the release of [3H] dopamine from the median eminence in vitro. This latter effect was dose dependent. In young rats, a single injection of bPRL minimally reduced the concentration of plasma PRL between 100 min and 5 h, but by 22-25 h it decreased plasma PRL to approximately one third of preinjection levels. The magnitude of the PRL pulses, but not the pulse frequency was significantly reduced after administration of bPRL treatment to young rats. Treatment with BSA did not alter the concentration of plasma PRL or the magnitude and frequency of the PRL pulses in young rats. In old rats, plasma PRL concentrations and the frequency and magnitude of the PRL pulses were not significantly decreased after injection of either bPRL or BSA. Thus, the feedback inhibition of PRL on PRL release may not be operative in old rats. The loss of the short loop feedback inhibition of PRL is believed to be due to the reduction in hypothalamic dopaminergic activity previously reported by our and other laboratories in old rats.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
113
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1452-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Failure of prolactin short loop feedback mechanism to operate in old as compared to young female rats.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.