Linked Life Data

10856892

Source:http://linkedlifedata.com/resource/pubmed/id/10856892

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-8-17
pubmed:abstractText
Thyrotropin (TSH) is secreted not as one distinct hormone, but rather as a group of isohormones which differ in their oligosaccharide composition. Although the mechanisms regulating TSH glycosylation are not fully understood, there is strong evidence that TRH plays an important role. The aim of our study was to determine the dynamic influence of TRH on TSH microheterogeneity. Sera were obtained from euthyroid volunteers (n=20) before and 30, 60, 120, 180 and 240 min after intravenous, nasal and oral administration of TRH in three independent runs (randomized order, at a time-interval of 3 weeks between each run). TSH was immuno-concentrated and analysed by isoelectric focusing (IEF) and lentil lectin affinity chromatography. TSH immunoreactivity was measured by an automated second-generation TSH immunoassay. Overall, serum TSH concentrations reached maximal values 30 min after intravenous, 60 min after nasal and 180 min after oral TRH stimulation. IEF analysis revealed 63.3+/-3.3% of pituitary standard TSH (IRP 80/558) in the neutral pH range (8>pH>6). In contrast, 30 min after TRH stimulation 80.8+/-3.7% (P<0.001) and 60 min after TRH stimulation 44.9+/-2.2% (P<0.001) of the TSH of euthyroid probands were found in this pH range, whereas 180 min after TRH stimulation 58.4+/-2.3% (P<0.001) were detected in the acidic pH range (pH<6). This shift of TSH composition in euthyroidism after TRH stimulation was confirmed by lentil lectin analysis of TSH: core-fucose content of euthyroid TSH was 73.4+/-3.8% 30 min and 22.9+/-3.2% 120 min after TRH stimulation in contrast to basal (53.3+/-1.8%; P<0.001) and pituitary standard (IRP 80/558) TSH (63.0+/-0.9%; P<0.001). In conclusion, in euthyroidism, TRH stimulation time-dependently changes the distribution pattern of the TSH isoforms from an alkaline and neutral to a more acidic one. This corresponds to the secretion of isohormones with altered bioactivity which could influence the fine-tuning of thyroid function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-0795
pubmed:author
pubmed:issnType
Print
pubmed:volume
166
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
137-43
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Thyrotropin-releasing hormone time-dependently influences thyrotropin microheterogeneity--an in vivo study in euthyroidism.
pubmed:affiliation
Max-Planck Institut für Psychiatrie, Endokrinologie und Klinische Chemie, D-80804 München, Germany. schaaf@mpipsykl.mpg.de
pubmed:publicationType
Journal Article, Clinical Trial, Comparative Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't