Adefovir is transported by the organic anion transporter (OAT1) and the multidrug resistant protein (MRP2, 4 and 5).
Thyroid hormones carriers (overlapping with Adefovir)
Besides hOAT1 , other renal transporters may also potentially contribute to active tubular accumulation of these drugs. Among others, recently identified rat organic anion transporting polypeptide (oatp) type 3 is expressed almost exclusively in kidney, and transports organic anions like thyroxine or taurocholic acid
J Neurochem. 2004 Aug;90(3):743-9.Click here to read Links
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Localization of organic anion transporting polypeptide 3 (oatp3) in mouse brain parenchymal and capillary endothelial cells.
Ohtsuki S, Takizawa T, Takanaga H, Hori S, Hosoya K, Terasaki T.
Department of Molecular Biopharmacy and Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai, Japan.
Organic anion transporting polypeptide 3 (oatp3) transports various CNS-acting endogenous compounds, including thyroid hormones and prostaglandin E2, between extra- and intracellular spaces, suggesting a possible role in CNS function . The purpose of this study was to clarify the expression and localization of oatp3 in the mouse brain. RT-PCR analysis revealed that oatp3 mRNA is expressed in brain capillary-rich fraction, conditionally immortalized brain capillary endothelial cells, choroid plexus , brain and lung, but not in liver or kidney, where oatp1, 2 and 5 mRNAs were detected. Immunohistochemical analysis with anti-oatp3 antibody suggests that oatp3 protein is localized at the brush-border membrane of mouse choroid plexus epithelial cells . Furthermore, intense immunoreactivity was detected in neural cells in the border region between hypothalamus and thalamus, and in the olfactory bulb. Immunoreactivity was also detected in brain capillary endothelial cells in the cerebral cortex. These localizations in the mouse brain suggest that oatp3 plays roles in blood-brain and -cerebrospinal fluid barrier transport of organic anions and signal mediators, and in hormone uptake by neural cells.
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Efflux of T3 from different cell types is saturable, but saturable efflux of T4 has not yet been demonstrated. Saturable uptake of T4 and T3 in the brain occurs both via the blood-brain barrier and the choroid plexus-cerebrospinal fluid barrier
Plasma Membrane Transport of Thyroid Hormones and Its Role in Thyroid Hormone Metabolism and Bioavailability 2001
Mutations in the SLC16A2 gene cause Allan-Herndon-Dudley syndrome.
The SLC16A2 gene (OMIM), also known as MCT8, provides instructions for making a protein that plays a critical role in the development of the nervous system. This protein transports a particular hormone into nerve cells in the developing brain. This hormone, called triiodothyronine or T3, is produced by a butterfly-shaped gland in the lower neck called the thyroid. T3 appears to be critical for the normal formation and growth of nerve cells, as well as the development of junctions between nerve cells (synapses) where cell-to-cell communication occurs. T3 and other forms of thyroid hormone also help regulate the development of other organs and control the rate of chemical reactions in the body (metabolism).
Gene mutations alter the structure and function of the SLC16A2 protein. As a result, this protein is unable to transport T3 into nerve cells effectively. A lack of this critical hormone in certain parts of the brain disrupts normal brain development, resulting in intellectual disability and problems with movement. Because T3 is not taken up by nerve cells, excess amounts of this hormone continue to circulate in the bloodstream. Increased T3 levels in the blood may be toxic to some organs and contribute to the signs and symptoms of Allan-Herndon-Dudley syndrome.
Thyroid transcription factor-1 exhibits osmosensitive transcription in brain-derived cell lines. 2008
Papers oatp3 + thyroid
