Linked Life Data

414907

Source:http://linkedlifedata.com/resource/pubmed/id/414907

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1978-4-26
pubmed:abstractText
The hypothalamic content and concentration of thyrotropin-releasing hormone (TRH) were determined by radioimmunoassay in normal, thyroidectomized, hypophysectomized and cold-exposed rats with or without thyroxine. In normal animals, the single administration of thyroxine (1,5 and 20 microgram/100 g B.W.) altered neither the content nor the concentration of TRH in the hypothalamus. However, seven days' administration of this hormone resulted in the dose-dependent increase in the hypothalamic TRH levels. In thyroidectomized rats the hypothalamic TRH levels were slightly reduced in spite of the marked increase of plasma TSH levels and decrease of pituitary TSH levels. In the animals given thyroxine (10 microgram/100 g B.W.) for 7 days in addition to thyroidectomy, however, the TRH levels exceeded that in the animals which underwent throidectomy alone. The hypothalamic TRH levels were markedly reduced in hypophysectomized rats. Conversely, in hypophysectomized rats given 7 days' thyroxine (1 and 5 microgram/100 g B.W.), the levels were increased dose-dependently. In cold-exposed rats, the plasma TSH levels roughly doubled, but the TRH levels remained unchanged. These findings strongly suggest that the feedback site of thyroxine extends not only to the pituitary gland but also to the hypothalamus, and that thyroxine has an increasing effect of the hypothalamic TRH level, though the mechanism(s) remain to be clarified.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0013-7219
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
537-43
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Effects of thyroxine and cold exposure on hypothalamic TRH levels in rats with various pituitary-thyroid states.
pubmed:publicationType
Journal Article