Transmucosal movement of selenium

McConnell, Kenneth P.; Cho, Gloria J.

doi:10.1152/ajplegacy.1965.208.6.1191

Cited by 95 publications

(45 citation statements)

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“…q'Selenomethionine ('SeM) follows the metabolic pathway of methionine and is incorporated into proteins (21)(22)(23); it provides the technical advantage of producing gamma emissions. The isotope previously has been used to study the production of red blood cells (24,25).…”

Section: Introductionmentioning

confidence: 99%

Measurement of thrombopoiesis in rabbits using 75selenomethionine

Evatt¹,

Levin²

1969

J. Clin. Invest.

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A B S T R A C T Incorporation of 'selenomethionine ('SeM) has been used to study platelet production in rabbits. Radioactivity of platelets was low after the intravenous administration of 'SeM and rose to a maximum approximately 3 days after administration. Platelet radioactivity was independent of concurrent plasma levels. The life span of rabbit platelets, as estimated with this technique, was 4-5 days. In vivo reutilization of '7SeM previously incorporated into plasma proteins was not detected. In vitro incorporation of 'SeM by platelets in platelet-rich plasma was not demonstrated.Acute hemorrhage 24 hr before administration of 'SeM increased the incorporation of 'SeM into platelets. Transfusion-induced thrombocytosis reduced the incorporation of 'SeM to approximately 30% of that observed in control animals. Suppression of bone marrow function with nitrogen mustard resulted in decreased numbers of platelets in the circulation, and a decrease in incorporation of 'SeM. Delayed appearance of '7SeM was observed in circulating platelets during recovery from marrow suppression. Injection of 75-225 ml of plasma from thrombocytopenic donors into normal rabbits increased incorporation of 'SeM into platelets while normal plasma did not have this effect.The rate of appearance of 'SeM in circulating platelets appears to provide a sensitive and specific method for the study of production of platelets by megakaryocytes. The data suggest more rapid entry of platelets into the circulation, and a sustained increase in incorporation of 'SeM into platelet protein after stimulation of platelet production. The results are consistent with the concept of a humoral agent (thrombopoietin) that acts on megakaryocytes to regulate platelet production.

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Section: Introductionmentioning

confidence: 99%

Measurement of thrombopoiesis in rabbits using 75selenomethionine

Evatt¹,

Levin²

1969

J. Clin. Invest.

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“…Empirical S. Misra, R. W. M. Kwong and S. Niyogi evidence with human lymphocytes (Porter et al, 1979) and hamster intestine (McConnell and Cho, 1965) demonstrated this previously. The lack of energy dependency is consistent with the assumption of anion exchanger-mediated selenite transport, as such a facilitative transport system is driven by concentration gradients to mediate net bidirectional release or uptake of substrates.…”

Section: Discussionmentioning

confidence: 61%

“…The diverse speciation of selenium suggests that the cellular uptake of selenium is likely to occur via multiple membrane transporters, depending on its discrete chemical forms. Early work by McConnell and Cho suggested a passive transport of inorganic selenium (selenite) in the intestine of golden hamster (McConnell and Cho, 1965). Further investigation with human lymphocytes also indicated that the transport of selenite is a passive process and sensitive to sulfhydryl inhibitors (Porter et al, 1979).…”

Section: Introductionmentioning

confidence: 99%

Transport of selenium across the plasma membrane of primary hepatocytes and enterocytes of rainbow trout

Misra

Kwong

Niyogi

2012

Journal of Experimental Biology

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SUMMARYTransport of essential solutes across biological membranes is one of the fundamental characteristics of living cells. Although selenium is an essential micronutrient, little is known about the cellular mechanisms of chemical species-specific selenium transport in fish. We report here the kinetic and pharmacological transport characteristics of selenite and its thiol (glutathione and L-cysteine) derivatives in primary cultures of hepatocytes and isolated enterocytes of rainbow trout. Findings from the current study suggest an apparent low-affinity linear transport system for selenite in both cell types. However, we recorded high-affinity Hill kinetics (K d 3.61±0.28mmoll -1 ) in enterocytes exposed to selenite in the presence of glutathione. The uptake of selenite in the presence of thiols was severalfold higher than uptake of selenite alone (at equimolar concentration) in both hepatocytes and enterocytes. Cellular accumulation of selenium was found to be energy independent. Interestingly, we observed a decrease in selenite transport with increasing pH, whereas selenite uptake increased with increasing pH in the presence glutathione in both cell types. The cellular uptake of selenite demonstrated a pronounced competitive interaction with a structurally similar compound, sulfite. The uptake of selenite as well as its thiol derivatives was found to be sensitive to the anion transport blocker DIDS, irrespective of the cell type. Inorganic mercury (Hg 2+) elicited an inhibition of selenite transport in both cell types, but augmented the transport of reduced forms of selenite in hepatocytes. Based on the substrate choice and comparable pharmacological properties, we advocate that multiple anion transport systems are probably involved in the cellular transport of selenite in fish. Supplementary material available online at

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“…The Se used in this experiment was mainly present in the form of Se [Met]. Se [Met] can be an excellent analogue for Met in biochemical reactions because of the similar covalent radio of Se and S. As McConnell and Cho(1965) Sunde and Evenson (1987). The same effect of Met on the utilization of the deposited tissue Se for GSH-Px synthesis was reported by Waschulewski and Sunde (1988b).…”

Section: Tbars Contentmentioning

confidence: 99%