Linked Life Data

2499891

Source:http://linkedlifedata.com/resource/pubmed/id/2499891

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1989-7-21
pubmed:abstractText
Neuromedin B (NB), a bombesin-like peptide, was first isolated from porcine spinal cord and subsequently found in the central nervous systems of rat, cat, and human. Immunocytochemical studies have shown that NB is present in hypothalamus and various other regions of the brain and in thyrotrophs of the anterior pituitary of the rat. The possible physiological role of NB in the hypothalamic-pituitary axis is not known. Therefore, we studied the in vivo effect of this peptide on the plasma levels of thyrotropin (TSH) after administering NB to conscious freely moving adult male rats. When injected i.v., only the highest dose of NB (50 micrograms, 44.2 nmol) significantly lowered plasma TSH levels relative to levels in saline controls. When injected intraventricularly, NB doses of 0.5 and 5 micrograms (0.44 and 4.42 nmol, respectively) lowered plasma TSH levels with a 15-min latency period. Responsiveness of the pituitary to TSH-releasing hormone (TRH) was tested after the effective dose of NB was administered i.v. The increase in plasma TSH levels after the i.v. injection of 1 microgram of TRH was not altered by NB. NB at 10(-9) to 10(-7) M also reduced TSH release from hemipituitaries incubated in vitro without decreasing the response to TRH. Consequently, NB appears to have a direct inhibitory effect on TSH release from thyrotrophs. Since the response to TRH was not depressed, NB appears to act on a separate NB thyrotroph receptor that suppresses TSH release by a TRH-independent mechanism. After antiserum directed against NB was injected into the third ventricle, there was a highly significant elevation of the plasma level of TSH, beginning at 4 hr and increasing at 6 hr, relative to initial levels and levels in normal rabbit serum-injected controls. These results indicate that NB has a tonic suppressive effect on TSH release and is a physiologically significant TSH-release-inhibitory factor.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:volume
86
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4789-92
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Role of neuromedin B in the control of the release of thyrotropin in the rat.
pubmed:affiliation
Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235-9040.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.