The hepatic retinyl ester hydrolase activity is depressed at the onset of diabetes in BB rats

Chen, Min; Thomson, A. B. R.; Tsin, Andrew; Basu, Tapan K.

doi:10.1079/bjn2002753

Cited by 9 publications

(9 citation statements)

References 29 publications

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“…( 7 ) Hepatic retinyl ester hydrolase activity in type 1 diabetic model rats was repressed, which agreed with the elevated retinol levels detected in the liver. ( 17 ) The previous reports speculate impaired metabolic availability of retinol and disturbed secretion of retinol from the liver in the type 1 diabetic state. ( 18 , 19 ) In contrast, Goto-Kakizaki (GK) rats, a type 2 diabetes model, presented higher plasma retinol and RBP levels than the control rats.…”

Section: Discussionmentioning

confidence: 98%

Altered retinol status and expression of retinol-related proteins in streptozotocin-induced type 1 diabetic model rats

Takitani

Inoue

Koh

et al. 2015

J. Clin. Biochem. Nutr.

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Diabetes is a metabolic disorder characterized by chronic hyperglycemia. Advanced diabetes is associated with severe complications and impaired nutritional status. Here, we assessed the expression of retinol-associated proteins, including β-carotene 15,15'-monooxygenase (BCMO), lecithin:retinol acyltransferase (LRAT), aldehyde dehydrogenase (ALDH), and cytochrome P450 26A1 (CYP26A1), and measured retinol levels in the plasma and liver of streptozotocin (STZ)-induced type 1 diabetic model rats. Compared to the levels in the control rats, retinol levels in the plasma and liver of STZ rats were decreased and increased, respectively. Hepatic expression of the LRAT gene in STZ rats was lower than that in the controls. In the liver of STZ rats, the expression of ALDH1A1, a retinal metabolizing enzyme was higher, whereas ALDH1A2 expression was lower than in the controls. Hepatic CYP26A1 expression in STZ rats was significantly higher than in the control rats. BCMO expression levels in the liver and intestine of STZ rats were much lower than those of the controls. Altered BCMO expression might affect retinol status. It is considered that the metabolic availability of retinol was lessened despite the accelerated catabolism of retinol; therefore, retinol mobilization may be unbalanced in the liver of rats in the type 1 diabetic state.

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Section: Discussionmentioning

confidence: 98%

Altered retinol status and expression of retinol-related proteins in streptozotocin-induced type 1 diabetic model rats

Takitani

Inoue

Koh

et al. 2015

J. Clin. Biochem. Nutr.

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“…Interestingly, the hepatic concentrations of retinol remained high in these diabetic animals, which were further elevated when supplemented with vitamin A, indicating a blockade of vitamin A mobilization that is solely dependent on RBP4 (47,48,51). This is further supported by the observation that retinyl ester hydrolase activity in liver was found to be decreased in T1D rat models, but not in intestine, in agreement with increased hepatic accumulation without changes in the intestinal absorption of retinol (51). It is also possible that the decrease in plasma retinol and/or RBP4 could be a result of increased renal filtration due to low plasma TTR concentrations during T1D (40,41).…”

Section: Plasma Rbp4 Ttr and Retinol Levels In Type 1 Diabetesmentioning

confidence: 95%

“…In fact, the intake of food and hence vitamin A is markedly increased in STZ-induced diabetic rats (41,50). Interestingly, the hepatic concentrations of retinol remained high in these diabetic animals, which were further elevated when supplemented with vitamin A, indicating a blockade of vitamin A mobilization that is solely dependent on RBP4 (47,48,51). This is further supported by the observation that retinyl ester hydrolase activity in liver was found to be decreased in T1D rat models, but not in intestine, in agreement with increased hepatic accumulation without changes in the intestinal absorption of retinol (51).…”

Section: Plasma Rbp4 Ttr and Retinol Levels In Type 1 Diabetesmentioning

confidence: 98%

Contrasting effects of type 2 and type 1 diabetes on plasma RBP4 levels: The significance of transthyretin

et al. 2012

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SummaryRetinol-binding protein 4 (RBP4) is the principle carrier of retinol in the human plasma, which circulates as a complex with transthyretin (TTR), a homotetrameric thyroxine transport protein. Although this complex formation is thought to prevent glomerular filtration of RBP4, it also stabilizes the quaternary structure of TTR. Recent studies indicate elevated plasma levels of RBP4 in type 2 diabetes (T2D). In contrast, reduced RBP4 levels were observed in type 1 diabetes (T1D). Herein, we critically examine the probable mechanisms involved in the regulation of RBP4 and TTR levels during T2D and T1D. The available evidences point to the involvement of pancreatic factors in regulating the expression of both RBP4 and TTR. It appears that during T1D, TTR levels are reduced and it exists predominantly as a monomer that may interfere its interaction with RBP4 resulting in its loss through glomerular filtration. However, plasma TTR levels remain high under T2D conditions and thus reducing glomerular filtration of RBP4. Therefore, the plasma TTR levels appear to be an important determinant of plasma RBP4 levels in these two diabetic conditions. 2012 IUBMB IUBMB Life, 64(12): 975-982, 2012

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“…Dr. Basu's recent research investigation on diabetes is another major break through in the contemporary nutritional research realm. He was been the first researcher to report that type 1 diabetes (T1D) is associated with impaired meta-bolic availability of vitamin A due to its decreased hepatic hydrolysis as well as the synthesis of its carrier protein and that this secondary deficiency of the vitamin is linked to diabetes-related retinopathy [48,[51][52][53][54][55][56][57][58][59]. The subnormal vitamin A status in poorly controlled diabetic subject does not seem to respond to vitamin A supplementation but rather it increases its load in the liver leading to hepatoxicity [60].…”

Section: Dr T K Basu's Research Profile and Our Common Research Inmentioning

confidence: 99%

Genotype X Environment Interactions and Its Impact on Use of Medicinal Plants

Acharya¹,

Basu²,

Banik³

et al. 2010

TONUTRAJ

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There is a paradigm shift from cure to prevention when it comes to human health. We want to live a healthy life and prevent sickness using substances other than pharmaceuticals. The plant-based nutraceutical products or Natural Health Products (NHPs) as they are some times referred to are the most important groups that have the potential to fit the bill. However, these products are sold without proper science based information in spite of the fact that most researchers acknowledge the need for such information. Evidence-based scientific studies to support health and nutraceutical claims related to the use of medicinal plants and their extracts have to be undertaken. It is only through critical research efforts that we can provide strong endorsements for medicinal plant use and ensure consumer confidence in the industry. Much of the research published on the medicinal value of plants does not take into account variability generated from genetic differences among plants and their interaction with the environment. Research should be directed towards properly identifying plants with known medicinal properties which have been grown in environments that are conducive to consistent production of the active agents attributed to the plants. Production of dependable medicinal plant products can only be attained if we pay close attention to these research-based principles. This article was written with main goals: 1) To discuss the above points in greater detail with examples; and 2) to highlight life time accomplishments and significant contributions of a well respected nutritionist Dr. T. K. Basu and his collaboration in development of fenugreek as a NHP. We believe that collaboration among clinical and agricultural researchers is essential to make the NHPs utilized to its potential and the plants (parts such as seed, foliage or roots) should be developed to the extent that they can be used directly to take advantage of the synergistic effect of the chemical constituents.

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The hepatic retinyl ester hydrolase activity is depressed at the onset of diabetes in BB rats

Cited by 9 publications

References 29 publications

Altered retinol status and expression of retinol-related proteins in streptozotocin-induced type 1 diabetic model rats

Altered retinol status and expression of retinol-related proteins in streptozotocin-induced type 1 diabetic model rats

Contrasting effects of type 2 and type 1 diabetes on plasma RBP4 levels: The significance of transthyretin

Genotype X Environment Interactions and Its Impact on Use of Medicinal Plants

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