scholarly journals Impact of Oatp1c1 Deficiency on Thyroid Hormone Metabolism and Action in the Mouse Brain

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1528-1537 ◽  
Author(s):  
Steffen Mayerl ◽  
Theo J. Visser ◽  
Veerle M. Darras ◽  
Sigrun Horn ◽  
Heike Heuer

Organic anion-transporting polypeptide 1c1 (Oatp1c1) (also known as Slco1c1 and Oatp14) belongs to the family of Oatp and has been shown to facilitate the transport of T4. In the rodent brain, Oatp1c1 is highly enriched in capillary endothelial cells and choroid plexus structures where it may mediate the entry of T4 into the central nervous system. Here, we describe the generation and first analysis of Oatp1c1-deficient mice. Oatp1c1 knockout (KO) mice were born with the expected frequency, were not growth retarded, and developed without any overt neurological abnormalities. Serum T3 and T4 concentrations as well as renal and hepatic deiodinase type 1 expression levels were indistinguishable between Oatp1c1 KO mice and control animals. Hypothalamic TRH and pituitary TSH mRNA levels were not affected, but brain T4 and T3 content was decreased in Oatp1c1-deficient animals. Moreover, increased type 2 and decreased type 3 deiodinase activities indicate a mild hypothyroid situation in the brain of Oatp1c1 KO mice. Consequently, mRNA expression levels of gene products positively regulated by T3 in the brain were down-regulated. This central nervous system-specific hypothyroidism is presumably caused by an impaired passage of T4 across the blood-brain barrier and indicates a unique function of Oatp1c1 in facilitating T4 transport despite the presence of other thyroid hormone transporters such as Mct8.

Endocrinology ◽  
2009 ◽  
Vol 150 (3) ◽  
pp. 1078-1083 ◽  
Author(s):  
Heike Heuer ◽  
Theo J. Visser

Thyroid hormone metabolism and action are largely intracellular events that require transport of iodothyronines across the plasma membrane. It has been assumed for a long time that this occurs by passive diffusion, but it has become increasingly clear that cellular uptake and efflux of thyroid hormone is mediated by transporter proteins. Recently, several active and specific thyroid hormone transporters have been identified, including monocarboxylate transporter 8 (MCT8), MCT10, and organic anion transporting polypeptide 1C1 (OATP1C1). The latter is expressed predominantly in brain capillaries and transports preferentially T4, whereas MCT8 and MCT10 are expressed in multiple tissues and are capable of transporting different iodothyronines. The pathophysiological importance of thyroid hormone transporters has been established by the demonstration of MCT8 mutations in patients with severe psychomotor retardation and elevated serum T3 levels. MCT8 appears to play an important role in the transport of thyroid hormone in the brain, which is essential for the crucial action of the hormone during brain development. It is expected that more specific thyroid hormone transporters will be discovered in the near future, which will lead to a better understanding of the tissue-specific regulation of thyroid hormone bioavailability. Specific thyroid hormone transporters may be discovered in the near future, leading to a better understanding of the tissue-specific regulation of thyroid hormone bioavailability.


Author(s):  
Navin Patil ◽  
Karthik Rao ◽  
Humeera Naaz ◽  
Balaji Ommurugan ◽  
Gayathri Baiju ◽  
...  

Hypothyroidism is a clinical syndrome due to deficiency of thyroid hormone. Thyroid hormone is responsible for maintaining the brain hemostasis and helps in central nervous system global development. There have been studies on the association of psychiatric illness with thyroid deficiency and strikingly found to be presenting feature of hypothyroidism in many patients. Literature evidence also says that underlying hypothyroidism may lead to failure of psychiatric treatment. Hence, we report a case of hypertensive patient on medications started with antidepressants and antipsychotics after being diagnosed of depression but was found to be resistant to psychiatric medications and later successfully treated with levothyroxine for underlying hypothyroidism with myxedema.


Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5294-5305 ◽  
Author(s):  
Brittany L. Mason ◽  
Carmine M. Pariante ◽  
Sara Jamel ◽  
Sarah A. Thomas

Proper functioning of the hypothalamic-pituitary-adrenal axis depends on the ability of glucocorticoids (GCs), mainly cortisol in humans and corticosterone in rodents, to access brain targets and regulate their own secretion. Being highly lipophilic, GCs have been assumed to passively diffuse through the cell membrane. However, the access of these GCs to the brain may be a more complicated process, because the free movement of molecules into the central nervous system (CNS) is restricted by the presence of the blood-brain and blood-cerebrospinal fluid barriers. GCs do interact with some transporter systems, including the efflux transporter, P-glycoprotein, and members of the organic anion transporter polypeptide (oatp) family, both of which have been found at the blood-CNS barriers. Using an in situ brain/choroid plexus perfusion, P-glycoprotein was shown to not majorly regulate the access of [3H]cortisol and [3H]corticosterone to the choroid plexus or pituitary gland. Interactions of [3H]cortisol and [3H]corticosterone with saturable influx transporters were detected at the hypothalamus, cerebellum, choroid plexus, and pituitary gland. Oatp2 seems to have some role in the influx of [3H]cortisol and [3H]corticosterone to the choroid plexus and the pituitary gland and other transporters, unlikely to be oatp2, may play a very minor role in the access of [3H]cortisol and [3H]corticosterone to the brain, as well as having a significant effect on [3H]glucocorticoid receptor accumulation in the pituitary gland. Overall, these data suggest that the majority of cortisol and corticosterone present in the plasma diffuse into the CNS and that transporters do not play a major role in the accumulation of these GCs in the brain.


Author(s):  
S.S. Spicer ◽  
B.A. Schulte

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.


2012 ◽  
Vol 13 (2) ◽  
pp. 32-42 ◽  
Author(s):  
Yvette D. Hyter

Abstract Complex trauma resulting from chronic maltreatment and prenatal alcohol exposure can significantly affect child development and academic outcomes. Children with histories of maltreatment and those with prenatal alcohol exposure exhibit remarkably similar central nervous system impairments. In this article, I will review the effects of each on the brain and discuss clinical implications for these populations of children.


2018 ◽  
Vol 23 (1) ◽  
pp. 10-13
Author(s):  
James B. Talmage ◽  
Jay Blaisdell

Abstract Injuries that affect the central nervous system (CNS) can be catastrophic because they involve the brain or spinal cord, and determining the underlying clinical cause of impairment is essential in using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), in part because the AMA Guides addresses neurological impairment in several chapters. Unlike the musculoskeletal chapters, Chapter 13, The Central and Peripheral Nervous System, does not use grades, grade modifiers, and a net adjustment formula; rather the chapter uses an approach that is similar to that in prior editions of the AMA Guides. The following steps can be used to perform a CNS rating: 1) evaluate all four major categories of cerebral impairment, and choose the one that is most severe; 2) rate the single most severe cerebral impairment of the four major categories; 3) rate all other impairments that are due to neurogenic problems; and 4) combine the rating of the single most severe category of cerebral impairment with the ratings of all other impairments. Because some neurological dysfunctions are rated elsewhere in the AMA Guides, Sixth Edition, the evaluator may consult Table 13-1 to verify the appropriate chapter to use.


2018 ◽  
Vol 25 (28) ◽  
pp. 3333-3352 ◽  
Author(s):  
Natalia Pessoa Rocha ◽  
Ana Cristina Simoes e Silva ◽  
Thiago Ruiz Rodrigues Prestes ◽  
Victor Feracin ◽  
Caroline Amaral Machado ◽  
...  

Background: The Renin-Angiotensin System (RAS) is a key regulator of cardiovascular and renal homeostasis, but also plays important roles in mediating physiological functions in the central nervous system (CNS). The effects of the RAS were classically described as mediated by angiotensin (Ang) II via angiotensin type 1 (AT1) receptors. However, another arm of the RAS formed by the angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and the Mas receptor has been a matter of investigation due to its important physiological roles, usually counterbalancing the classical effects exerted by Ang II. Objective: We aim to provide an overview of effects elicited by the RAS, especially Ang-(1-7), in the brain. We also aim to discuss the therapeutic potential for neuropsychiatric disorders for the modulation of RAS. Method: We carried out an extensive literature search in PubMed central. Results: Within the brain, Ang-(1-7) contributes to the regulation of blood pressure by acting at regions that control cardiovascular functions. In contrast with Ang II, Ang-(1-7) improves baroreflex sensitivity and plays an inhibitory role in hypothalamic noradrenergic neurotransmission. Ang-(1-7) not only exerts effects related to blood pressure regulation, but also acts as a neuroprotective component of the RAS, for instance, by reducing cerebral infarct size, inflammation, oxidative stress and neuronal apoptosis. Conclusion: Pre-clinical evidence supports a relevant role for ACE2/Ang-(1-7)/Mas receptor axis in several neuropsychiatric conditions, including stress-related and mood disorders, cerebrovascular ischemic and hemorrhagic lesions and neurodegenerative diseases. However, very few data are available regarding the ACE2/Ang-(1-7)/Mas receptor axis in human CNS.


Author(s):  
Asfree Gwanyanya ◽  
Christie Nicole Godsmark ◽  
Roisin Kelly-Laubscher

Abstract: Ethanolamine is a bioactive molecule found in several cells, including those in the central nervous system (CNS). In the brain, ethanolamine and ethanolamine-related molecules have emerged as prodrug moieties that can promote drug movement across the blood-brain barrier. This improvement in the ability to target drugs to the brain may also mean that in the process ethanolamine concentrations in the brain are increased enough for ethanolamine to exert its own neurological ac-tions. Ethanolamine and its associated products have various positive functions ranging from cell signaling to molecular storage, and alterations in their levels have been linked to neurodegenerative conditions such as Alzheimer’s disease. This mini-review focuses on the effects of ethanolamine in the CNS and highlights the possible implications of these effects for drug design.


Author(s):  
Elizabeth Hampson

Organizational and activational effects of sex steroids were first discovered in laboratory animals, but these concepts extend to hormonal actions in the human central nervous system. This chapter begins with a brief overview of how sex steroids act in the brain and how the organizational-activational hypothesis originated in the field of endocrinology. It then reviews common methods used to study these effects in humans. Interestingly, certain cognitive functions appear to be subject to modification by sex steroids, and these endocrine influences may help explain the sex differences often seen in these functions. The chapter considers spatial cognition as a representative example because the spatial family of functions has received the most study by researchers interested in the biological roots of sex differences in cognition. The chapter reviews evidence that supports an influence of both androgens and estrogens on spatial functions, and concludes with a glimpse of where the field is headed.


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