Linked Life Data

194701

Source:http://linkedlifedata.com/resource/pubmed/id/194701

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1977-8-12
pubmed:abstractText
The ultrastruct of the tanycyte ependyma in male 160-180 g Wistar albino rats was studied under normal conditions and in experiments involving long-term suppression of ACTH secretion and its long-term stimulation. The former was accomplished by daily (for 8 days) intraperitoneal administration of dexamethasone phosphate at low (5 microgram/100 g) and high (100 microgram/100 g) concentrations. The effectiveness of suppression of the hypothalamic-hypophyseal-adrenal system in the experimental animals was judged by their reaction to two-minute ether stress (determination of plasma corticosterone) and by the results of measurement of the adrenal weights. Stimulation of ACTH secretion was achieved by bilateral adrenalectomy; the animals were examined on days 8, 10, 14, and 22 following the operation. The results obtained were in agreement with the previously established fact that there is a negative correlation between tanycyte activity and hypophyseal adrenocorticotropic function (Akmayed and Fidelina, 1974). They also testified to the predominant involvement of the median eminence tanycyte ependyma (beta-tanycytes according to the author's nomenclature) in these relationships. It is supposed that correlations are regulated by a feedback mechanism and attest to the involvement of beta-tanycytes in the inhibiting control of hypophyseal adrenocorticotrophic function. The mechanism of this control may be explained alternatively: either the tanycytes transport ACTH-suppression substances (catecholamines, corticosteroids, ACTH) from the CSF to the hypophyseal portal system or they themselves secrete substances possessing ACTH-suppressive activity. The authors distinguish several types of vesicles in the beta-tanycytes, the number of which changed with experimentally induced shifts in hypophyseal adrenocorticotrophic function. These vesicles are discussed in connection with the transport and secretory activity of the tanycytes and are considered to be a possible substrate of the hypothalamic inhibiting effect on ACTH secretion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0302-766X
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
180
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
263-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Morphological aspects of the hypothalamic-hypophyseal system. VII. The tanycytes: Their relation to the hypophyseal adrenocorticotrophic function. An ultrastructural study.
pubmed:publicationType
Journal Article