Linked Life Data

3104015

Source:http://linkedlifedata.com/resource/pubmed/id/3104015

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1987-4-27
pubmed:abstractText
Hypothalamic-pituitary-end-organ axes are frequently controlled by long loop negative feedback homeostatic mechanisms. Insulin-like growth factor I (IGF-I), IGF-II, and insulin receptors have recently been described in normal and neoplastic rat and acromegalic human pituitary cells, a finding which suggests the possibility that somatomedins might exert feedback at the level of the anterior pituitary. To study the kinetics of this feedback response, we used perifused dispersed rat anterior pituitary cells to learn if somatomedins or insulin could inhibit GH-releasing hormone (GHRH)-stimulated GH secretion. Cells were exposed to hourly boluses of 1 nM GHRH with or without varying doses of IGF or insulin. IGF-I inhibited GHRH-elicited GH release with an IC50 of 6.5 nM; maximal inhibition (approximately 67%) was achieved with 10 nM IGF-I. IGF-II was a less potent hormone, with 10 nM inhibiting about 30% of GHRH-stimulated GH release. Slight inhibition of stimulated GH release (less than 15%) was seen when cells were treated with insulin, but only when doses of insulin of 10 nM or more were used. In conclusion, nanomolar concentrations of IGF-I and IGF-II inhibited GHRH-elicited GH release from perifused rat pituitary cells in a dose-dependent manner; and insulin was not an effective inhibitor of stimulated GH release at physiological peptide concentrations. In conjunction with our previous findings that the concentrations of IGF-I and IGF-II receptors greatly exceed that of insulin receptors on normal rat pituitary cells, we hypothesize that the GH-inhibiting action of high dose insulin is mediated through an IGF receptor.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
120
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1658-62
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
The growth hormone (GH)-releasing hormone (GHRH)-GH-somatomedin axis: evidence for rapid inhibition of GHRH-elicited GH release by insulin-like growth factors I and II.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't