Lack of Action of Exogenously Administered T3 on the Fetal Rat Brain Despite Expression of the Monocarboxylate Transporter 8
| Autor: | Beatriz Morte, Gabriella Morreale de Escobar, Juan Bernal, Carmen Grijota-Martínez, Diego Diez |
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| Rok vydání: | 2011 |
| Předmět: |
Monocarboxylic Acid Transporters
medicine.medical_specialty Organic Cation Transport Proteins Endocrinology Diabetes and Metabolism Clinical Biochemistry Fluorescent Antibody Technique Organic Anion Transporters Nerve Tissue Proteins Biochemistry Endocrinology Internal medicine Gene expression medicine Animals Rats Wistar Monocarboxylate transporter Pregnancy Fetus Microscopy Confocal biology Membrane transport protein business.industry Biochemistry (medical) Intracellular Signaling Peptides and Proteins Brain Transporter Compartment (chemistry) medicine.disease Rats Thyroxine medicine.anatomical_structure Cerebral cortex biology.protein Amino Acid Transport Systems Basic Triiodothyronine Female business Calcium-Calmodulin-Dependent Protein Kinase Type 4 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/en.2010-1014 |
| Popis: | Mutations of the monocarboxylate transporter 8 gene (MCT8, SLC16A2) cause the Allan-Herndon-Dudley syndrome, an X-linked syndrome of severe intellectual deficit and neurological impairment. Mct8 transports thyroid hormones (T4 and T3), and the Allan-Herndon-Dudley syndrome is likely caused by lack of T3 transport to neurons during critical periods of fetal brain development. To evaluate the role of Mct8 in thyroid hormone action in the fetal brain we administered T4 or T3 to thyroidectomized pregnant dams treated with methyl-mercapto-imidazol to produce maternal and fetal hypothyroidism. Gene expression was then measured in the fetal cerebral cortex. T4 increased Camk4, Sema3c, and Slc7a3 expression, but T3 was without effect. To investigate the cause for the lack of T3 action we analyzed the expression of organic anion transport polypeptide (Oatp14, Slco1c1), a T4 transporter, and Mct8 (Slc16a2), a T4 and T3 transporter, by confocal microscopy. Both proteins were present in the brain capillaries forming the blood-brain barrier and in the epithelial cells of the choroid plexus forming the blood-cerebrospinal fluid barrier. It is concluded that T4 from the maternal compartment influences gene expression in the fetal cerebral cortex, possibly after transport via organic anion transporter polypeptide and/or Mct8, and conversion to T3 in the astrocytes. On the other hand, T3 does not reach the target neurons despite the presence of Mct8. The data indicate that T4, through local deiodination, provides most T3 in the fetal rat brain. The role of Mct8 as a T3 transporter in the fetal rat brain is therefore uncertain. Copyright © 2011 by The Endocrine Society. This work was supported by Grants SAF2008-01168 and SAF2008-00429E from the Ministry of Science and Innovation, Spain, the European Union Integrated Project CRESCENDO (LSHM-CT-2005-018652), and by the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III. D.D. was supported by the I3P program of the Consejo Superior de Investigaciones Científicas, Spain and by a postdoctoral fellowship from The Japanese Society for the Promotion of Science. |
| Databáze: | OpenAIRE |
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