Linked Life Data

6861693

Source:http://linkedlifedata.com/resource/pubmed/id/6861693

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1983-8-11
pubmed:abstractText
An acute injection of estradiol is known to cause a rapid redistribution of estrogen receptors in responsive cells, measurable as depletion of the cytosol receptor content with accompanying accumulation in the nucleus. We have examined the effects of progesterone on this process in the anterior pituitary and hypothalamus using an animal model in which sensitivity to steroidal feedback control of gonadotropin secretion has been defined. Ovariectomized immature rats were administered low dose estrogen replacement for 4 days. On the morning of the fifth day, groups of animals were injected according to one of the following protocols: 1) vehicle alone; 2) 5 or 10 micrograms estradiol; and 3) 0.8 or 3.2 mg progesterone, followed 1 h later by vehicle or 5 or 10 micrograms estradiol. All animals were killed 1 h after estradiol (or vehicle) injection, and levels of cytosol and nuclear estrogen receptors were measured. The only change occasioned by progesterone treatment was a decrease in anterior pituitary nuclear estrogen receptor levels. At the 5-microgram dose of estradiol, 0.8 and 3.2 mg progesterone were equally effective in diminishing nuclear estrogen receptor binding. When 10 micrograms estradiol were used to cause receptor redistribution, only the higher 3.2-mg dose of progesterone significantly depressed nuclear receptor binding. If ovariectomized animals were maintained in the absence of estrogen replacement, progesterone at either the 0.8- or 3.2-mg dosage was completely ineffective in altering the patterns of estradiol-induced cytosol or nuclear estrogen receptor levels. The results demonstrate a tissue-specific inhibitory action of progesterone on estrogen-induced enhancement of nuclear estrogen receptor binding. This inhibition can be partially overcome by increasing the level of estrogen used to effect receptor redistribution. The requirement for maintenance of a background level of estrogen suggests that the inhibitory action of progesterone is mediated through progesterone receptor interactions.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
113
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15-22
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Analysis of the effect of progesterone in vivo on estrogen receptor distribution in the rat anterior pituitary and hypothalamus.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.