Linked Life Data

3651233

Source:http://linkedlifedata.com/resource/pubmed/id/3651233

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1987-11-10
pubmed:abstractText
Progesterone (P) action following estrogen priming is required normally for the facilitation of estrous behavior in female rats. Although mechanisms by which P exerts its influence on estrous responsiveness have not been elucidated, the primary site of action of P has been shown to be the ventromedial nucleus of the hypothalamus (VMN). The objective of the present series of experiments was to describe the temporal parameters of P action in the VMN in the facilitation of estrous behavior in estrogen-primed female rats. Subjects were female Long-Evans rats stereotaxically outfitted with 23-ga. guide cannulae directed towards the VMN. Crystalline P was applied directly to the brain tissue via bilateral 28-ga. insert cannulae, which could be inserted and removed easily through the guide cannulae. Animals were ovariectomized and estrogen primed with 5% estradiol Silastic capsules. They received a counterbalanced series of two experimental tests: one involving a manipulation with a P-filled implant, and another with a blank implant. In the first experiment, a significant increase in estrous responsiveness occurred only after 2 hr exposure of the VMN to P, whereas 4 hr were required for a full display of estrous behavior, including solicitation. In Experiment 2, P was lowered into the brain for either 1, 2, or 4 hr, and testing took place 4 hr after the lowering of the implant. It was found that 2 hr of P exposure was sufficient to facilitate full estrous responsiveness at 4 hr. In Experiment 3, it was revealed that the duration of estrous responsiveness was directly related to the time the P implant remained in the brain. In the fourth experiment, the time course of P retention in brain tissue, revealed by determination of 3H-progesterone levels in hypothalamus, agreed with the behavioral findings. Progesterone levels in the region of the VMN remained high while a P implant was in place, but declined rapidly after removal. A dual mechanistic hypothesis for P action in the facilitation of estrous behavior is presented.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0735-7044
pubmed:author
pubmed:issnType
Print
pubmed:volume
101
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
534-45
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Temporal aspects of ventromedial hypothalamic progesterone action in the facilitation of estrous behavior in the female rat.
pubmed:affiliation
Department of Biological Sciences, Rutgers University, Piscataway, New Jersey 08854.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't