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Tissue-Specific Alterations in Thyroid Hormone Homeostasis in Combined Mct10 and Mct8 Deficiency

Authors :
Heike Heuer
Theo J. Visser
Julia Müller
Steffen Mayerl
Anita Boelen
Veerle Darras
François Verrey
Luca Mariotta
Lucien Frappart
Internal Medicine
AGEM - Amsterdam Gastroenterology Endocrinology Metabolism
Laboratory for Endocrinology
University of Zurich
Heuer, Heike
Source :
Endocrinology, 155(1), 315-325. Endocrine Society, Endocrinology, 155(1), 315-325. The Endocrine Society
Publication Year :
2014
Publisher :
Endocrine Society, 2014.

Abstract

The monocarboxylate transporter Mct10 (Slc16a10; T-type amino acid transporter) facilitates the cellular transport of thyroid hormone (TH) and shows an overlapping expression with the well-established TH transporter Mct8. Because Mct8 deficiency is associated with distinct tissue-specific alterations in TH transport and metabolism, we speculated that Mct10 inactivation may compromise the tissue-specific TH homeostasis as well. However, analysis of Mct10 knockout (ko) mice revealed normal serum TH levels and tissue TH content in contrast to Mct8 ko mice that are characterized by high serum T3, low serum T4, decreased brain TH content, and increased tissue TH concentrations in the liver, kidneys, and thyroid gland. Surprisingly, mice deficient in both TH transporters (Mct10/Mct8 double knockout [dko] mice) showed normal serum T4 levels in the presence of elevated serum T3, indicating that the additional inactivation of Mct10 partially rescues the phenotype of Mct8 ko mice. As a consequence of the normal serum T4, brain T4 content and hypothalamic TRH expression were found to be normalized in the Mct10/Mct8 dko mice. In contrast, the hyperthyroid situation in liver, kidneys, and thyroid gland of Mct8 ko mice was even more severe in Mct10/Mct8 dko animals, suggesting that in these organs, both transporters contribute to the TH efflux. In summary, our data indicate that Mct10 indeed participates in tissue-specific TH transport and also contributes to the generation of the unusual serum TH profile characteristic for Mct8 deficiency.

Details

ISSN :
19457170 and 00137227
Volume :
155
Issue :
1
Database :
OpenAIRE
Journal :
Endocrinology
Accession number :
edsair.doi.dedup.....a3145a7265ccad08108bb3d52fa42aff