Glucose Transport in Isolated Brush Border Membrane from Rat Small Intestine

Hopfer, Ulrich; Nelson, K.; Perrotto, Joseph L.; Isselbacher, Kurt J.

doi:10.1016/s0021-9258(19)44440-2

Cited by 806 publications

(35 citation statements)

References 27 publications

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“…The adult (~3 mo old) male mouse primary PAC and liver mitochondria were isolated as described previously (6, 34, 38 -40). The freshly prepared mitochondria were suspended in uptake buffer [140 mM KCl, 0.3 mM EDTA, 5 mM MgCl 2, 10 mM MES, 10 mM HEPES, and 10 mM succinate (to maintain the function of mitochondria), pH 7.4] and then immediately used for uptake studies using a rapid-filtration technique (17,34,40). The mitochondria (20 l; containing ϳ15-20 g/l of protein) were added to the uptake buffer (80 l) containing [ 3 H]TPP (0.38 M) at the onset of incubation at 37°C.…”

Section: Methodsmentioning

confidence: 99%

Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

Sabui

Subramanian

Kapadia

et al. 2017

American Journal of Physiology-Gastrointestinal and Liver Physi

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The essentiality of thiamin stems from its roles as a cofactor [mainly in the form of thiamin pyrophosphate (TPP)] in critical metabolic reactions including oxidative energy metabolism and reduction of cellular oxidative stress. Like other mammalian cells, pancreatic acinar cells (PAC) obtain thiamin from their surroundings and convert it to TPP; mitochondria then take up TPP by a carrier-mediated process that involves the mitochondrial TPP (MTPP) transporter (MTPPT; product of gene). Previous studies have characterized different physiological/biological aspects of the MTPP uptake process, but little is known about its possible adaptive regulation. We addressed this issue using pancreatic acinar 266-6 cells (PAC 266-6) maintained under thiamin-deficient (DEF) and oversupplemented (OS) conditions, as well as thiamin-DEF and -OS transgenic mice carrying the promoter. We found that maintaining PAC 266-6 under the thiamin-DEF condition leads to a significant induction in mitochondrial [H]TPP uptake, as well as in the level of expression of the MTPPT protein and mRNA compared with thiamin-OS cells. Similar findings were observed in mitochondria from thiamin-DEF mice compared with thiamin-OS. Subsequently, we demonstrated that adaptive regulation of MTTP protein was partly mediated via transcriptional mechanism(s) via studies with PAC 266-6 transfected with the promoter and transgenic mice carrying the promoter. This transcriptional regulation appeared to be, at least in part, mediated via epigenetic mechanism(s) involving histone modifications. These studies report, for the first time, that the PAC mitochondrial TPP uptake process is adaptively regulated by the prevailing thiamin level and that this regulation is transcriptionally mediated and involves epigenetic mechanism(s). Our findings show, for the first time, that the mitochondrial thiamin pyrophosphate (MTPP) uptake process is adaptively regulated by the prevailing thiamin level in pancreatic acinar cells and this regulation is mediated, at least in part, by transcriptional and epigenetic mechanism(s) affecting the promoter.

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Section: Methodsmentioning

confidence: 99%

Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

Sabui

Subramanian

Kapadia

et al. 2017

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…Transport studies using hepatopancreatic BBMV were generally conducted at 15 °C using a temperature-controlled water bath and the Millipore filtration technique developed by Hopfer, Nelson, Perrotto & Isselbacher (1973). Two types of transport experiments were performed.…”

Section: Methodsmentioning

confidence: 99%

Electroneutral Na+-2 Cl−-Leucine Cotransport by Lobster Hepatopancreatic Brush-Border Membrane Vesicles

Ahearn

Clay

1988

Journal of Experimental Biology

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Uptake of L-[3H]leucine by lobster hepatopancreatic brush-border membrane vesicles was stimulated by a transmembrane NaCl gradient (o>i), but not by identical gradients of NaSCN or other Cl− salts (e.g. K+, Li+, NH4+, Cs+ or choline), suggesting that amino acid transfer depended upon both Na+ and Cl−. In NaCl medium at acidic pH, leucine uptake was largely electroneutral and unresponsive to a transmembrane potential generated by permeable anions; however, in Na+-free medium, amino acid transport was strongly electrogenic under the same conditions. Leucine influx occurred by a combination of two carrier processes at physiologically acidic pH. One exhibited an influx Kt of 0.59 mmol l−1, a JM of 390 pmol mg protein−1 S−1 and a cotransport stoichiometry of 1 Na+: 2 Cl+: 1 leucine. This process was most strongly cis-inhibited by the non-polar amino acids phenylalanine, methionine and isoleucine, and most weakly inhibited by the more polar species methylaminoisobutyric acid (MeAIB), hydroxyproline, glutamate and arginine. The second leucine carrier system showed a very low binding affinity and could not be distinguished from diffusion, was Na+- and Cl−-independent, and was cis-inhibited by more polar amino acids such as lysine, hydroxyproline, MeAIB, alanine and glutamate. These results suggest that brush-border leucine transport in lobster hepatopancreas at acidic pH may occur by a combination of a modified L-system, that includes ion cosubstrates, and either by a second undefined Na+-independent process with a broad structural specificity or by multiple Na+-independent processes.

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“…Testing the antiglycemic effects of Momordica and the combined formula using Brush Border Membrance Vesicle model via its glucose uptake obstruction [21][22][23].…”

Section: IIImentioning

confidence: 99%

An Evidence-Based Herbal Supplement for The Control of Metabolic Syndrome

Wat¹,

Koon²,

Lau³

et al. 2020

ADO

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Background: Metabolic Syndrome (MS): Overweight, Obesity, Hypertension, Hyperglycemia and Hypercholesterolemia, are generally accepted today as clinical signals leading to cardiovascular diseases. Control of MS is therefore of a common health concern. While drug treatment is yet not available or may not be creditable, developing an effective health supplement against MS is highly justified. Methods:A herbal formula composed of four herbs known to have anti MS pathological effects was used for in vivo and in vitro biological researches to verify its pharmacological effect, and subsequent pilot clinical trial.Results: In vitro study: Adipocyte viability and cholesterol uptake, liver cell viability and anti-glycaemia effects, all gave positive results of good control. In vivo study testing herbal formula's effects on obese mice also showed very promising results. In clinical trial, measurements of body weight, body circumferences, BMI, as well as liver fibrosis, all showed good responses after the herbal formula consumption. Conclusion:Our efforts on the creation of an Evidence-Based Specific Supplement for the control of Metabolic Syndrome have harvested highly positive data in the laboratory. The subsequent 3 months' pilot clinical trial showed positive data on the control of blood lipids, general body measurements and liver steatosis.

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Glucose Transport in Isolated Brush Border Membrane from Rat Small Intestine

Cited by 806 publications

References 27 publications

Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

Electroneutral Na+-2 Cl−-Leucine Cotransport by Lobster Hepatopancreatic Brush-Border Membrane Vesicles

An Evidence-Based Herbal Supplement for The Control of Metabolic Syndrome

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