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Article: Thyroid hormones regulate the expression of somatostatin receptor subtypes in the rat pituitary

TitleThyroid hormones regulate the expression of somatostatin receptor subtypes in the rat pituitary
Authors
Issue Date1999
PublisherS Karger AG. The Journal's web site is located at http://www.karger.com/NEN
Citation
Neuroendocrinology, 1999, v. 69 n. 6, p. 460-464 How to Cite?
AbstractCirculating TSH levels are increased in hypothyroidism and suppressed in hyperthyroidism. On the other hand, the hypothalamic hormone somatostatin suppresses basal and TRH-induced TSH release, an effect which is enhanced by thyroid hormones. To investigate whether the effects of thyroid hormones on TSH secretion may be mediated in part through alterations in the gene expression of pituitary somatostatin receptors (SSTR), 3-week-old male Sprague-Dawley rats were rendered hypothyroid with antithyroid drugs for 3 weeks. Total RNA extracted from anterior pituitaries were analysed for SSTR mRNA levels, using Northern blot hybridization. Compared to controls, hypothyroid rats had significantly lower pituitary mRNA levels of SSTR1 and SSTR2 (p < 0.0001 for both, n = 16); the reductions could be prevented by T 4 supplementation (3 μg/100 g body weight/day i.p.). In vitro studies using GH 4C 1 rat pituitary cells showed that the addition of T 3 10 -8 M to cells cultured in charcoal-stripped bovine calf serum resulted in significant increases in mRNA levels of SSTR1 (p < 0.0001; n = 7) and the two transcripts of SSTR2 (p < 0.0005; n = 7). The increase for SSTR1 showed no further increase with higher doses of T 3, but was time-dependent and could be seen consistently after 8 h of incubation. We conclude that thyroid hormones regulate the gene expression of SSTR subtypes in the pituitary, via a direct action on anterior pituitary cells. Changes in SSTR gene expression may contribute to the increase in circulating TSH levels in hypothyroidism.
Persistent Identifierhttp://hdl.handle.net/10722/76850
ISSN
2015 Impact Factor: 2.583
2015 SCImago Journal Rankings: 1.479
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLam, KSLen_HK
dc.contributor.authorWong, RLCen_HK
dc.date.accessioned2010-09-06T07:25:35Z-
dc.date.available2010-09-06T07:25:35Z-
dc.date.issued1999en_HK
dc.identifier.citationNeuroendocrinology, 1999, v. 69 n. 6, p. 460-464en_HK
dc.identifier.issn0028-3835en_HK
dc.identifier.urihttp://hdl.handle.net/10722/76850-
dc.description.abstractCirculating TSH levels are increased in hypothyroidism and suppressed in hyperthyroidism. On the other hand, the hypothalamic hormone somatostatin suppresses basal and TRH-induced TSH release, an effect which is enhanced by thyroid hormones. To investigate whether the effects of thyroid hormones on TSH secretion may be mediated in part through alterations in the gene expression of pituitary somatostatin receptors (SSTR), 3-week-old male Sprague-Dawley rats were rendered hypothyroid with antithyroid drugs for 3 weeks. Total RNA extracted from anterior pituitaries were analysed for SSTR mRNA levels, using Northern blot hybridization. Compared to controls, hypothyroid rats had significantly lower pituitary mRNA levels of SSTR1 and SSTR2 (p < 0.0001 for both, n = 16); the reductions could be prevented by T 4 supplementation (3 μg/100 g body weight/day i.p.). In vitro studies using GH 4C 1 rat pituitary cells showed that the addition of T 3 10 -8 M to cells cultured in charcoal-stripped bovine calf serum resulted in significant increases in mRNA levels of SSTR1 (p < 0.0001; n = 7) and the two transcripts of SSTR2 (p < 0.0005; n = 7). The increase for SSTR1 showed no further increase with higher doses of T 3, but was time-dependent and could be seen consistently after 8 h of incubation. We conclude that thyroid hormones regulate the gene expression of SSTR subtypes in the pituitary, via a direct action on anterior pituitary cells. Changes in SSTR gene expression may contribute to the increase in circulating TSH levels in hypothyroidism.en_HK
dc.languageengen_HK
dc.publisherS Karger AG. The Journal's web site is located at http://www.karger.com/NENen_HK
dc.relation.ispartofNeuroendocrinologyen_HK
dc.rightsNeuroendocrinology. Copyright © S Karger AG.en_HK
dc.subject.meshAnimalsen_HK
dc.subject.meshBlotting, Northernen_HK
dc.subject.meshCells, Cultureden_HK
dc.subject.meshMaleen_HK
dc.subject.meshPituitary Gland - drug effects - metabolismen_HK
dc.subject.meshPituitary Gland, Anterior - drug effects - metabolismen_HK
dc.subject.meshRNA, Messenger - biosynthesisen_HK
dc.subject.meshRatsen_HK
dc.subject.meshRats, Sprague-Dawleyen_HK
dc.subject.meshReceptors, Somatostatin - metabolismen_HK
dc.subject.meshThyroid Hormones - physiologyen_HK
dc.subject.meshThyrotropin - blooden_HK
dc.subject.meshThyroxine - blooden_HK
dc.titleThyroid hormones regulate the expression of somatostatin receptor subtypes in the rat pituitaryen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0028-3835&volume=69&spage=460&epage=464&date=1999&atitle=Thyroid+hormones+regulate+the+expression+of+somatostatin+receptor+subtypes+in+the+rat+pituitaryen_HK
dc.identifier.emailLam, KSL:ksllam@hku.hken_HK
dc.identifier.authorityLam, KSL=rp00343en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1159/000054450en_HK
dc.identifier.pmid10364699-
dc.identifier.scopuseid_2-s2.0-0033060156en_HK
dc.identifier.hkuros41464en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0033060156&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume69en_HK
dc.identifier.issue6en_HK
dc.identifier.spage460en_HK
dc.identifier.epage464en_HK
dc.identifier.isiWOS:000081075200009-
dc.publisher.placeSwitzerlanden_HK
dc.identifier.scopusauthoridLam, KSL=8082870600en_HK
dc.identifier.scopusauthoridWong, RLC=37062742700en_HK

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