Intestinal Permeability of Water-Soluble Nonelectrolytes: Sugars, Amino Acids, Peptides

Esposito, Giovanni

doi:10.1007/978-3-642-69505-6_15

Cited by 11 publications

(7 citation statements)

References 237 publications

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“…Results of these experiments (Fig. 4) indicate that the compound 2-deoxy-D-glucose, which is specific for the Na +-independent trans¬ port mechanism (Esposito, 1984), was at least as efficacious as glucose in inhibiting 3-OMG transport. 4-a-Methyl-glucoside, which has a high affinity for the Na + -dependent system, was only slightly more effective than fructose at inhibiting the 3-OMG flux.…”

Section: Transport Specificitymentioning

confidence: 89%

“…The dose-response relationships of phlorizin, an inhibitor of Na +-dependent hexose transport, and of phloretin, which inhibits Na +-independent hexose transport (Esposito, 1984), were exam¬ ined for Day-6 p.c. embryos (Fig.…”

Section: Transport Inhibitorsmentioning

confidence: 99%

“…The first is a sodium-coupled glucose transporter which is found in the apical border of absorptive epithelia (e.g. digestive tract and proximal tubule of the nephron; reviewed by Ullrich, 1979;Esposito, 1984). Glucose transport by this system is inhibited by phlorizin, and, indirectly, by ouabain.…”

Section: Introductionmentioning

confidence: 99%

“…The second glucose transport system involves a carrier mechanism which operates independently of sodium (Kinne et ai, 1975;Gliemann & Rees, 1983). This transport system has been extensively studied in adipose tissue, brain and the human erythrocyte, and is also located on the basolateral membrane of the enterocyte and the proximal tubule cell (Kinne et ai, 1975;Esposito, 1984). This transport system is pharmacologically distinct from the sodium coupled system in that cytochalasin and phloretin are potent, specific inhibitors, while phlorizin is without effect.…”

Section: Introductionmentioning

confidence: 99%

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Hexose transport in preimplantation rabbit blastocysts

Robinson¹,

Smith²,

Benos³

1990

Reproduction

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Summary. Transtrophectodermal 3-0-methyl glucose (3-0MG) transport in the rabbit blastocyst at Days 6 and 7 post coitum was investigated to understand better how the trophectoderm can regulate inner cell mass growth by controlling substrate availability. 3-0MG rapidly traversed the trophectoderm and displayed saturation kinetics (Km = 4\m=.\3 \ m=+-\ 0\m=.\5 mM, Vmax =79 \m=+-\ 3\m=.\8 nmol.cm\p=n-\2). The flux of 3-0MG was inhibited nearly 95% by 10\p=n-\4M-phloretin, and only 15% by 10\p=n-\4 M-phlorizin. Furthermore, 3\ x =r eq-\ OMG influx was inhibited by cytochalasin B (5 \g=m\M) and was unaffected by removal of sodium. The transport system had a high specificity for 2-deoxy-D-glucose and glucose, and a very low specificity for fructose and 4-\g=a\-methylglucoside. Western blots probed with a polyclonal antibody to the human erythrocyte glucose transport protein and also with a polyclonal antibody to the C-terminus of the glucose transport protein of the rat brain revealed a broad band with a molecular weight of 55 000. Using immunogold labelling techniques, Na +-independent glucose transporters were localized to both the apical and basolateral borders of the trophectodermal cell. These results suggest that the mechanism in the trophectoderm responsible for transport of glucose is similar to other sodium-independent glucose transport systems. In addition, 3-0MG influx was unaffected by short-term incubation with progesterone, the progesterone antagonist mifepristone (RU-486), PGF-2\g=a\,PGE-2, insulin, or cAMP. Day-7 p.c. embryos also transported hexoses by a similar system because the influx rate and the phlorizin/ phloretin sensitivity were the same as in the Day-6 p.c. embryo.

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Section: Transport Specificitymentioning

confidence: 89%

Section: Transport Inhibitorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hexose transport in preimplantation rabbit blastocysts

Robinson¹,

Smith²,

Benos³

1990

Reproduction

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“…Bağırsak lümeni içinde, pankreatik endopeptidazlar (özellikle de tripsin, elastas ve kimotripsin), eksopeptidazlar (karboksipeptidaz A ve B) yardımıyla amino asitler ve 2-6 amino asit uzunluğunda peptitler üretilmektedir. Daha sonra özel taşıma sistemleri bunları enterosit sitoplazmaya taşır (13,14). Her ne kadar tetrapeptit taşınmasına rastlanmışsa da (15), büyük yan zincirli dipeptit ve tripeptitler ve doğal L-konfigürasyonlar tercih edilmektedir.…”

Section: Metaboli̇zma Ve İtrahunclassified

Peptit yapılı ilaçların rasyonel tasarımına yönelik yeni gelişmeler: recent advances towards the rational design of peptide drugs

Yeşilada¹

2004

Ankara Universitesi Eczacilik Fakultesi Dergisi

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ÖZET ABSTRACTIn this review, after a short introduction to definition and physiological roles of regulatory peptides, problems faced during the development of peptide drugs, studies directed to solve these problems and rational design of peptide drugs with special emphesis on peptidomimetics are mentioned.Key Words: Peptides, endojen peptides, peptidomimetics, back-bone modifications GİRİŞGeçtiğimiz on-onbeş yıl içinde, hastalıkların teşhisi ve tedavisinde önemli gelişmeler olmuştur. Endojen peptitlerin ve proteinlerin hayati olayların düzenlenmesinde oynadıkları rolün öneminin anlaşılması bu gelişmelere ivme kazandıran önemli bir aşamadır. Doğal peptitlerin ilaç olarak kullanılması 1960'lı yılların başlarına kadar uzanmaktadır. Oksitosin, lis-vasopressin, kortikotropin, pentagastrin gibi hormonların sentezi ve piyasaya sürülmesi ile yaşanan bu dönemi , yetmişli yıllarda bir çok laboratuarın kapanmasına neden olan durgun bir dönem takip etmiştir.Bunun nedenleri doğal peptitlerin dayanıksız olmaları nedeniyle etki sürelerinin kısa olması,

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