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dc.contributor.authorFarwell, Alan P.
dc.contributor.authorDubord-Tomasetti, Susan A.
dc.date2022-08-11T08:10:02.000
dc.date.accessioned2022-08-23T16:52:52Z
dc.date.available2022-08-23T16:52:52Z
dc.date.issued1999-08-28
dc.date.submitted2008-07-09
dc.identifier.citation<p>Endocrinology. 1999 Sep;140(9):4221-7.</p>
dc.identifier.issn0013-7227 (Print)
dc.identifier.pmid10465295
dc.identifier.urihttp://hdl.handle.net/20.500.14038/42144
dc.description.abstractIn the rat cerebellum, migration of neurons from the external granular layer to the internal granular layer occurs postnatally and is dependent upon the presence of thyroid hormone. In hypothyroidism, many neurons fail to complete their migration and die. Key guidance signals to these migrating neurons are provided by laminin, an extracellular matrix protein that is fixed to the surface of astrocytes. Expression of laminin in the brain is developmentally timed to coincide with neuronal growth spurts. In this study, we examined the role of thyroid hormone on the expression and distribution of laminin in the rat cerebellum. We show that laminin content steadily increased 2- to 3-fold from birth to maximal levels on postnatal day 8-10 then steadily decreased to a plateau by postnatal day 12 in the euthyroid cerebellum. Immunoreactive laminin appeared in the molecular layer of the euthyroid cerebellum by postnatal day 4, reached maximal intensity by postnatal day 8-10, and was gone by postnatal day 14. In contrast, laminin content in the hypothyroid cerebellum remained unchanged from birth until postnatal day 10 and then increased to maximal levels over the next two days; maximal levels were approximately 35% less than those levels in the euthyroid cerebellum. Laminin staining did not appear in the molecular layer of the hypothyroid rat cerebellum until postnatal day 10, reached maximal intensity by postnatal day 15 and disappeared by postnatal day 18, despite the continued presence granular neurons in the external granular layer. These data indicate that the disruption of the timing of the appearance and regional distribution of laminin in the absence of thyroid hormone may play a major role in the profound derangement of neuronal migration observed in the cretinous brain.
dc.language.isoen_US
dc.relation<p><a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=10465295&dopt=Abstract">Link to Article in PubMed</a></p>
dc.relation.urlhttps://doi.org/10.1210/en.140.9.4221
dc.subjectAging
dc.subjectAnimals
dc.subjectAnimals, Newborn
dc.subjectAntithyroid Agents
dc.subjectCerebellum
dc.subjectHypothyroidism
dc.subjectImmunoblotting
dc.subjectImmunohistochemistry
dc.subjectLaminin
dc.subjectPropylthiouracil
dc.subjectRats
dc.subjectRats, Sprague-Dawley
dc.subjectThyroid Hormones
dc.subjectTissue Distribution
dc.subjectLife Sciences
dc.subjectMedicine and Health Sciences
dc.titleThyroid hormone regulates the expression of laminin in the developing rat cerebellum
dc.typeJournal Article
dc.source.journaltitleEndocrinology
dc.source.volume140
dc.source.issue9
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/518
dc.identifier.contextkey545000
html.description.abstract<p>In the rat cerebellum, migration of neurons from the external granular layer to the internal granular layer occurs postnatally and is dependent upon the presence of thyroid hormone. In hypothyroidism, many neurons fail to complete their migration and die. Key guidance signals to these migrating neurons are provided by laminin, an extracellular matrix protein that is fixed to the surface of astrocytes. Expression of laminin in the brain is developmentally timed to coincide with neuronal growth spurts. In this study, we examined the role of thyroid hormone on the expression and distribution of laminin in the rat cerebellum. We show that laminin content steadily increased 2- to 3-fold from birth to maximal levels on postnatal day 8-10 then steadily decreased to a plateau by postnatal day 12 in the euthyroid cerebellum. Immunoreactive laminin appeared in the molecular layer of the euthyroid cerebellum by postnatal day 4, reached maximal intensity by postnatal day 8-10, and was gone by postnatal day 14. In contrast, laminin content in the hypothyroid cerebellum remained unchanged from birth until postnatal day 10 and then increased to maximal levels over the next two days; maximal levels were approximately 35% less than those levels in the euthyroid cerebellum. Laminin staining did not appear in the molecular layer of the hypothyroid rat cerebellum until postnatal day 10, reached maximal intensity by postnatal day 15 and disappeared by postnatal day 18, despite the continued presence granular neurons in the external granular layer. These data indicate that the disruption of the timing of the appearance and regional distribution of laminin in the absence of thyroid hormone may play a major role in the profound derangement of neuronal migration observed in the cretinous brain.</p>
dc.identifier.submissionpathoapubs/518
dc.contributor.departmentMolecular Endocrinology Laboratory
dc.source.pages4221-7


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