Absorption of Zinc by the Rat Ileum: Effects of Histidine and Other Low-Molecular-Weight Ligands

Wapnir, Raul A.; Khani, Debra E.; Bayne, M A; Lifshitz, Fima

doi:10.1093/jn/113.7.1346

Cited by 91 publications

(34 citation statements)

References 21 publications

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“…Increasing intakes of dietary protein are associated with enhanced absorption,13 and it is believed that AAs that are released during digestion may play an important role in maintaining zinc solubility in the intestine, therefore aiding absorption 31. In rats, His enhances the absorption of zinc at a maximal rate at near physiological pH 32. In the present study, Arg was associated by linear regression to plasma zinc concentrations, and this association is consistent with the proposed role of AA.…”

Section: Discussionsupporting

confidence: 90%

Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

Samman

Crossett

Somers

et al. 2014

DMSO

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Amino acid (AA) status is determined by factors including nutrition, metabolic rate, and interactions between the metabolism of AA, carbohydrates, and lipids. Analysis of the plasma AA profile, together with markers of glucose and lipid metabolism, will shed light on metabolic regulation. The objectives of this study were to investigate the acute responses to the consumption of meals containing either pork (PM) or chicken (CM), and to identify relationships between plasma AA and markers of glycemic and lipemic control. A secondary aim was to explore AA predictors of plasma zinc concentrations. Ten healthy adults participated in a postprandial study on two separate occasions. In a randomized cross-over design, participants consumed PM or CM. The concentrations of 21 AA, glucose, insulin, triglycerides, nonesterified fatty acids, and zinc were determined over 5 hours postprandially. The meal composition did not influence glucose, insulin, triglyceride, nonesterified fatty acid, or zinc concentrations. Plasma histidine was higher following the consumption of PM (P=0.014), with consistently higher changes observed after 60 minutes (P<0.001). Greater percentage increases were noted at limited time points for valine and leucine + isoleucine in those who consumed CM compared to PM. In linear regression, some AAs emerged as predictors of the metabolic responses, irrespective of the meal that was consumed. The present study demonstrates that a single meal of PM or CM produces a differential profile of AA in the postprandial state. The sustained increase in histidine following the consumption of a PM is consistent with the reported effects of lean pork on cardiometabolic risk factors.

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Section: Discussionsupporting

confidence: 90%

Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

Samman

Crossett

Somers

et al. 2014

DMSO

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“…The inhibition observed with increasing peptide concentrations can be explained in terms of the peptide/Zn2+ ratio and saturation of the peptide transporter. Several authors obtained similar results with amino acids presenting a high affinity for zinc such as histidine and cysteine (Wapnir, Khani, Bayne & Lifshitz, 1983;Wapnir & Stiel, 1986;Wapnir, Lee & Stiel, 1989;Gachot, Tauc, Morat & Poujeol, 1991;Aiken, Horn & Saunders, 1992). They showed that zinc can 'follow' the amino acid through its specific carrier (i.e.…”

Section: Discussionmentioning

confidence: 72%

Mechanisms of zinc transport into pig small intestine brush‐border membrane vesicles.

Tacnet

Lauthier

Ripoche

1993

The Journal of Physiology

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SUMMARY1. The purpose of the present work was to examine certain membrane transport mechanisms likely to carry zinc across the brush-border membrane of pig small intestine, isolated in a vesicular form.2. In initial velocity conditions. saturation kinetics revealed a great effect of pH on zinc transport: optimal conditions were observed with an intravesicular pH of around 6-6 with or without a H+ gradient; however, this did not allow us to conclude the existence of a neutral exchange between Zn2+ and H+ ions.3. By measuring 36C1 uptakes, the presence of the Cl--HCO3-or Cl--OHantiporter with typical 4.4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) sensitivity was detected in vesicles; zinc did not alter this anionic exchange activity.A 65Zn time course, performed in conditions identical with those for 36C1 uptake, was DIDS insensitive and was greatly inhibited by an outward OH-gradient. This could argue against a transport of zinc as a complex with Cl-and HCO3-through the anion antiporter.4. When external Cl-and HCO3-were replaced by SCN-, able to form a Zn(SCN)42-complex, we observed a stimulating effect of outward HCO3-gradients on 65Zn uptake but neither DIDS nor diphenylamine-2-carboxylate (DPC) inhibited the transport in these conditions. This suggested that the intestinal anion antiporter was not a major route for zinc reabsorption.5. The tripeptide Gly-Gly-His at low concentrations stimulated 65Zn uptake, then inhibited it in a dose-dependent manner either in the presence of an inward H+ gradient or in the presence of a membrane potential 'negative inside' or in both situations. These conditions are necessary for the active transport of the peptide and this strongly suggests that zinc can be transported as a [Gly-Gly-His-Zn] complex, utilizing the peptide carrier system.

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“…medium was about 30 pmollpg D a A/h, in very good pmollpg DNA/ I T for our substrate concentration of 5 nM A large number of ligands have been proposed to serve as substrates for Zn uptake. These range from prostaglandin (Song and Adham, 1976), citric acid (Lonnerdal et al, 19801, metallothionein (Richards and Cousins, 1975), and histidine (Wapnir et al, 1983) in the gut, and prostaglandin (Evans andJohnson, 1977, citric acid (Hurley et al, 1979), and lactoferrin (Blakeborough et al, 19831, in human milk, and even a ZnHCO, carrier in red cells (Torrubia and Garay, 1989). Furthermore, Zn uptake by leucocytes and 3T3 cells is reduced in the presence of plasma and amino acids (Jones et al, 1981;Schwartz and Matrone, 1975).…”

Section: Time (Min)mentioning

confidence: 99%

Significance of extracellular zinc‐binding ligands in the uptake of zinc by human fibroblasts

Ackland

McArdle

1990

Journal Cellular Physiology

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Extracellular zinc (Zn)-binding ligands were investigated as vehicles for uptake of Zn by human fibroblasts. The uptake of alpha 2-macroglobulin, a major serum Zn-binding protein proposed to have a function in Zn transport, was less than 1/200 that of the Zn uptake rate. The fibroblast growth medium, BME with 10% FBS, contains several Zn-binding ligands. These were separated into components of MW greater than 30,000 and components of MW less than 30,000 using an Amicon microconcentrator. Cells accumulated Zn from both fractions; however, there was more uptake from the filtrate (MW less than 30,000), containing ligands with low affinity for Zn, hence with greater free Zn concentration. Zn uptake from a number of ligands with a range of affinities for Zn was examined and found to be inversely proportional to the Ka value for the ligands and therefore proportional to the free Zn concentration. When histidine and desferrioxamine, two structurally different Zn-binding ligands were compared, analysis of the concentration curves of calculated free Zn against Zn uptake gave similar Vmax and Km values (+/- S.E.M.) of 373 +/- 6 pmol/micrograms DNA/h and 0.08 +/- 0.004 microM for histidine, and 349 +/- 10 pmol/micrograms DNA/h and 0.06 +/- 0.008 microM for DFO, suggesting that the same transport mechanism was operating in both systems. We conclude that no specific ligands are essential for transport of Zn into fibroblasts, but that "free" Zn is acquired by the cell.

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Absorption of Zinc by the Rat Ileum: Effects of Histidine and Other Low-Molecular-Weight Ligands

Cited by 91 publications

References 21 publications

Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

Mechanisms of zinc transport into pig small intestine brush‐border membrane vesicles.

Significance of extracellular zinc‐binding ligands in the uptake of zinc by human fibroblasts

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