Zinc Binding: A Difference Between Human and Bovine Milk

Eckhert, CD; Sloan, MV; DUNCAN, .; Hurley, Lucille S.

doi:10.1126/science.836589

Cited by 154 publications

(26 citation statements)

References 12 publications

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“…The results presented here demonstrate that rat milk contained a ZBL similar in size to that found previously by us in human milk (1) and validate the use of the rat as a model to test the hypothesis that this ZBL may be involved in absorption of zinc in the neonate. A ZBL similar to that found in rat milk was identified in the rat intestine of 16-to 28-day-old animals but was absent in younger animals.…”

Section: Discussionsupporting

confidence: 87%

See 1 more Smart Citation

Zinc-binding ligands in milk and intestine: a role in neonatal nutrition?

Hurley¹,

Duncan²,

Sloan³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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The hythesis that a zinc-binding ligand (ZBL) recently discovered in human milk but absent from cow's milk might be related to zinc nutrition in the neonate was investigated. The zinc-binding characteristics of rat milk were examined to determine if the rat was a suitable model. By gel filtration, rat milk was found to contain a ZBL with characteristics similar to those of the ZBL found in human milk. A similar ZBL was identified in the intestinal mucosa of rats 16 days of age and older but was absent in rats from birth to 16 days. These results support the hypothesis that the ZBL of maternal milk may enhance zinc transport in the neonatal period before the development of intestinal mechanisms for zinc absorption. A recent report from this laboratory described the discovery in human milk of a low-molecular-weight zinc-binding ligand (ZBL) that is not present in cow's milk (1). We have proposed (1) that this ZBL is the factor responsible for the therapeutic value of human milk in the treatment of a genetic disorder of zinc metabolism, acrodermatitis enteropathica (AE), and that the ZBL acts by enhancing the absorption of zinc in patients suffering from this condition.AE is a hereditary disease in humans that appears in early infancy and is characterized by severe skin lesions, alopecia, and diarrhea (2). The onset of symptoms is frequently associated with the weaning of infants from breast milk to cow's milk (2-4). Without treatment, there is a relentless progression leading to death within I to 3 years (4). Since 1953, AE has been treated by oral administration of diiodohydroxyquin (Diodoquin) (5). Recently, Moynahan and Barnes (6) reported low plasma zinc levels in AE patients and successful treatment of the disorder with oral administration of zinc, the therapy resulting in an elevation of the plasma zinc and subsequent clearing of the epidermal lesions. The efficacy of zinc in the treatment of AE has been confirmed by other investigators (7,8). These findings indicate that the basic metabolic defect in this disorder is closely, if not directly, related to zinc metabolism, possibly at the level of zinc absorption as we proposed.We have also postulated that an intestinal ZBL necessary for zinc absorption is absent or immature at birth, even in normal individuals without AE, and that the ZBL of human milk may enable or enhance absorption of this element in the neonate until normal mechanisms of zinc absorption develop postnatally (9, 10). To test this hypothesis, we have used the rat as an experimental model. The present report describes the finding of a ZBL in rat milk similar to that present in human milk. In addition, the presence of a ZBL in the rat intestinal mucosa during the first few weeks of life was investigated.The costs of publication of this article were defrayed in part by the payment of page charges from funds made available to support the research which is the subject of the article. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely...

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Section: Discussionsupporting

confidence: 87%

“…Van Campen and Kowalski (12) have reported the presence of compounds of low molecular weight (10,(0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)000) Proc. Nati.…”

Section: Discussionmentioning

confidence: 99%

Zinc-binding ligands in milk and intestine: a role in neonatal nutrition?

Hurley¹,

Duncan²,

Sloan³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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“…The non-citrate bound zinc is also distributed similarly in the milk of the two species, but very different from most other species studied (16). As seen with iron absorption from human milk, it has been suggested that the high bioavailability of zinc from human milk relative to cow's milk may be due to a difference in molecular localization of zinc in the milks (9,24). The monkey thus presents a model in which this hypothesis may be tested.…”

Section: Methodsmentioning

confidence: 99%

“…The nonexchangeable space represents Ca2+ sequestered in su~cellular storage granules, and alteration of Ca" binding and/or.fluxes in the other compartments has an important role in the process of platelet aggregation and exocytosis (I). In subjects with Down's syndrome, blood platelets have decreased Na+/Kt-ATPase activity and increased intracellular Na+ (9). In erythrocytes, it has been reported that Na+/K+-ATPase is inhibited by increases in intracellular Ca2+ (2, 3), which may lead to raised intracellular Na+ (1 3); thus, it seemed pertinent to determine the Ca2+ content of blood platelets from subjects with Down's syndrome as a possible factor contributing to decreased Na+/K+-ATPase activity.…”

mentioning

confidence: 99%

A Longitudinal Study of Rhesus Monkey (Macaca mulatta) Milk Composition: Trace Elements, Minerals, Protein, Carbohydrate, and Fat

et al. 1984

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“…The chemical composition of human milk exhibits considerable variation between different individuals and in the same individual at different times of lactation (15), as well as between samples obtained from mothers of LBW infants and full term infants (16,17 (20). In addition, a zinc binding ligand, which promotes absorption of zinc, has been identified & the human milk (21,22): Human milk is considered to be deficient in vitamin D (9). Temporal studies of human milk have indicated that the concentration of many chemical components, especially nitrogen, calcium, and sodium decrease significantly as the duration of lactation increases (9, 10); however, several components have been found to change in concentration as a function of water content, because their total daily output appears to be remarkably constant at least during the first 8 wk of lactation (23,24).…”

Section: Composition Of Human Milkmentioning

confidence: 99%