Linked Life Data

9822802

Source:http://linkedlifedata.com/resource/pubmed/id/9822802

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1999-2-4
pubmed:abstractText
The biosynthesis of thyrotropin-releasing hormone (TRH) in the hypothalamic paraventricular nucleus (PVN) is subject to neural and hormonal regulations. To identify some of the potential effectors of this modulation, we incubated hypothalamic dispersed cells with dexamethasone for short periods of time (1-3 h) and studied the interaction of this hormone with protein kinase C (PKC) and PKA signaling pathways. TRH mRNA relative changes were determined by the RT-PCR technique. One hour incubation with 10(-10)-10(-4) M dexamethasone produced a concentration-dependent biphasic effect: an inhibition was observed on TRH mRNA levels at 10(-10) M, an increase above control at 10(-8)-10(-6) M and a reduction at higher concentrations (10(-5)- 10(-4) M). The stimulatory effect of 10(-8) M dexamethasone on TRH mRNA was essentially independent of new protein synthesis, as evidenced by cycloheximide pretreatment. Changes in TRH mRNA levels were reflected by enhanced TRH cell content. Incubation with a cAMP analogue (8-bromo-cAMP, 8Br-cAMP) or with a PKC activator (12-O-tetradecanoylphorbol-13-acetate, TPA) increased TRH mRNA levels after 1 and 2 h, respectively. An increase in TRH mRNA expression was observed by in situ hybridization of dexamethasone or 8Br-cAMP-treated cells. The interaction of dexamethasone, PKA and PKC signaling pathways was studied by combined treatment. The stimulatory effect of 10(-7) M TPA on TRH mRNA levels was additive to that of dexamethasone; in contrast, coincubation with 10(-3) M 8-Br-cAMP and dexamethasone diminished the stimulatory effect of both drugs. An inhibition was observed when the cAMP analogue was coincubated with TPA or TPA and dexamethasone. These results demonstrate that dexamethasone can rapidly regulate TRH biosynthesis and suggest a cross talk between cAMP, glucocorticoid receptors and PKC transducing pathways.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0028-3835
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
345-54
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Dexamethasone rapidly regulates TRH mRNA levels in hypothalamic cell cultures: interaction with the cAMP pathway.
pubmed:affiliation
Departamento de Genética y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't