Linked Life Data

19433492

Source:http://linkedlifedata.com/resource/pubmed/id/19433492

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2009-8-11
pubmed:abstractText
Growth hormone (GH) is secreted in a pulsatile fashion from the pituitary gland into the circulation. Release is governed by two hypothalamic neuropeptides, growth hormone-releasing hormone (GHRH) and somatostatin (SRIF), resulting in secretion episodes with a periodicity of 3.3 h in the male rat. Ghrelin is an additional recently identified potent GH-secretagogue. However, its in vivo interactions with the GH neuroendocrine axis remain to be elucidated. Moreover, two different sites of ghrelin synthesis are involved, the stomach and the hypothalamus. We used our previously developed core model of GH oscillations and added the sites of ghrelin action at the pituitary and in the hypothalamus. With this extended model, we simulated the effects of central and peripheral ghrelin injections, monitored the GH profile and compared it with existing experimental results. Systemically administered ghrelin elicits a GH pulse independent of SRIF, but only in the presence of GHRH. The peripheral ghrelin signal is mediated to the brain via the vagus nerve, where it augments the release of GHRH and stimulates the secretion of neuropeptide-Y (NPY). By contrast, centrally administered ghrelin initiates a GH pulse by increasing the GHRH level and by antagonizing the SRIF block at the pituitary. In addition, NPY neurons are activated, which trigger a delayed SRIF surge. The major novel features of the present model are a) the role played by NPY, and b) the dissimilar functions of ghrelin in the hypothalamus and at the pituitary. Furthermore, the predictions of the model were experimentally examined and confirmed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1479-6813
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
105-19
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Interactions of ghrelin signaling pathways with the GH neuroendocrine axis: a new and experimentally tested model.
pubmed:affiliation
Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't