Linked Life Data

3925360

Source:http://linkedlifedata.com/resource/pubmed/id/3925360

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1985-8-9
pubmed:abstractText
The effect of long-term decreases in circulating concentrations of prolactin was determined on the responsiveness of tuberoinfundibular dopamine (DA) neurons to this hormone. The activity of these neurons in ovariectomized rats was estimated by measuring the rate of DA synthesis (DOPA accumulation after the administration of a decarboxylase inhibitor) in the median eminence at various times after serum concentrations of prolactin had been reduced by hypophysectomy or the chronic administration of a DA agonist (bromocriptine, 3 mg/kg/day). The concentration of DA in the median eminence, but not in striatum, declined progressively up to 12 days after hypophysectomy, but did not change at any time during bromocriptine treatment. On the other hand, norepinephrine concentrations in the median eminence were increased 12 days after both treatments. Within 24 h after hypophysectomy or the first injection of bromocriptine the rate of DA synthesis in the median eminence was decreased; this decrease was maintained for at least 12 days suggesting that tuberoinfundibular DA neuronal activity is normally maintained by endogenous prolactin. Intracerebroventricular (ICV) injections of prolactin (10 micrograms, 12 h prior to sacrifice) increased the rate of DA synthesis in the median eminence of control, 24-hour hypophysectomized and 24-hour bromocriptine-treated rats. After longer periods (6-12 days) of bromocriptine treatment or after hypophysectomy the responsiveness of tuberoinfundibular DA neurons to prolactin was reduced. Dose-response studies revealed that the sensitivity and magnitude of response to ICV prolactin was markedly reduced in 12-day hypophysectomized rats.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0028-3835
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
369-76
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Hypoprolactinemia induced by hypophysectomy and long-term bromocriptine treatment decreases tuberoinfundibular dopaminergic neuronal activity and the responsiveness of these neurons to prolactin.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.