Linked Life Data

7913948

Source:http://linkedlifedata.com/resource/pubmed/id/7913948

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1994-8-30
pubmed:abstractText
The GH-releasing activity of the alpha 2-adrenergic agonist clonidine has been extensively studied in the rat, but the mechanism(s) by which clonidine stimulates GH release remains controversial. In the present study, we examined the effects of various doses of clonidine on spontaneous pulsatile GH secretion in conscious rats, and tested the hypothesis that the GH-releasing activity of clonidine is mediated primarily by an inhibition of hypothalamic somatostatin (SRIF) release. In the first experiment, free-moving adult male rats were given either saline or various doses of clonidine i.v. (30, 50 and 125 micrograms/kg) at times of spontaneous peaks (1100 h) and troughs (1300 h) in the GH rhythm. Clonidine, at all doses tested, failed to stimulate GH release when administered at the time of a spontaneous peak. In contrast, injection of clonidine at trough times (when SRIF tone is high) consistently augmented plasma GH levels (mean +/- S.E.M. integrated GH release; 30 micrograms/kg, 1843.0 +/- 484.0; 50 micrograms/kg, 1469.0 +/- 490.3; 125 micrograms/kg, 1675.6 +/- 513.4 vs 201.3 +/- 100.1 ng/ml per 45 min in saline-injected controls; p < 0.05 or less). No significant regression was observed between increasing doses of clonidine and GH release. In the second experiment, i.v. administration of 30 micrograms clonidine/kg during a GH trough period, 30 min prior to GH-releasing factor (GRF) challenge, significantly potentiated the GH response to GRF compared with rats given saline (7218.7 +/- 806.6 vs 4206.9 +/- 1068.1 ng/ml per 30 min; p < 0.05). Clonidine treatment, at all doses tested, resulted in hyperglycaemia and behavioural effects.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-0795
pubmed:author
pubmed:issnType
Print
pubmed:volume
141
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
259-66
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Evidence for a primary involvement of somatostatin in clonidine-induced growth hormone release in conscious rats.
pubmed:affiliation
Department of Pediatrics, McGill University, Quebec, Canada.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't