Linked Life Data

15103226

Source:http://linkedlifedata.com/resource/pubmed/id/15103226

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2004-4-30
pubmed:abstractText
Ghrelin, a novel 28-amino-acid peptide primarily expressed in stomach and hypothalamus, has recently emerged as the endogenous ligand for the GH-secretagogue receptor with ability to stimulate GH secretion in humans and rats. In addition, ghrelin also stimulates prolactin (PRL) secretion in humans. However, its role in the regulation of PRL secretion in rats remains largely unknown. In this context, the present experiments were carried out to analyze the effects of ghrelin on PRL secretion in male and female rats. In detail, the ontogeny and potential sexual dimorphism in the PRL response to ghrelin was evaluated. In addition, the hypothalamic and/or pituitary site of primary action of ghrelin, as well as the possible interactions between ghrelin and other neurotransmitters, as nitric oxide, dopamine, serotonin or excitatory amino acids, in the precise control of PRL secretion were assessed. Experiments were conducted in prepubertal male and female animals. Systemic (i.p.) and central (i.c.v.) administration of ghrelin significantly inhibited PRL secretion. Such an inhibitory effect became evident after day 10 of age, was similar in males and females, and was also observed in hyperprolactinemic aged female rats. In contrast, however, challenge of pituitary samples in vitro with increasing doses of ghrelin (10(-9)-10(-7)M) failed to inhibit PRL secretion. Analysis of interactions between ghrelin and other systems involved in the control of PRL secretion revealed that neither blockade of dopaminergic receptors with domperidone, nor enhancement of serotoninergic tone with fluoxetine + 5-hydroxytryptophan altered the inhibitory response to ghrelin in terms of PRL secretion. Similarly, blockade of nitric oxide synthases with L-nitro-arginine-methyl ester failed to modify the magnitude of ghrelin-induced inhibition of PRL secretion, whereas ghrelin was unable to further decrease serum PRL levels after activation of ionotropic excitatory amino acid receptors by administration of NMDA or AMPA. In conclusion, our data indicate that ghrelin is able to inhibit PRL secretion in male and female rats, likely through an extrapituitary primary site of action that is independent of nitric oxide, dopamine, and serotonin systems.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0028-3835
pubmed:author
pubmed:copyrightInfo
Copyright 2004 S. Karger AG, Basel
pubmed:issnType
Print
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
133-41
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:15103226-Age Factors, pubmed-meshheading:15103226-Animals, pubmed-meshheading:15103226-Dopamine, pubmed-meshheading:15103226-Down-Regulation, pubmed-meshheading:15103226-Excitatory Amino Acids, pubmed-meshheading:15103226-Female, pubmed-meshheading:15103226-Ghrelin, pubmed-meshheading:15103226-Hypothalamus, pubmed-meshheading:15103226-Injections, Intraperitoneal, pubmed-meshheading:15103226-Injections, Intraventricular, pubmed-meshheading:15103226-Male, pubmed-meshheading:15103226-Nitric Oxide, pubmed-meshheading:15103226-Peptide Hormones, pubmed-meshheading:15103226-Pituitary Gland, pubmed-meshheading:15103226-Prolactin, pubmed-meshheading:15103226-Rats, pubmed-meshheading:15103226-Serotonin, pubmed-meshheading:15103226-Sex Characteristics, pubmed-meshheading:15103226-Sexual Maturation
pubmed:year
2004
pubmed:articleTitle
Ghrelin inhibits prolactin secretion in prepubertal rats.
pubmed:affiliation
Department of Cell Biology, Physiology and Immunology, Physiology Section, Faculty of Medicine, University of Córdoba, Córdoba, Spain.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't