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H Gunshin

Publications and source records attributed to H Gunshin.

7 recordsLinked to original sources
PubMed2001

Iron-dependent regulation of the divalent metal ion transporter.

The first step in intestinal iron absorption is mediated by the H(+)-coupled Fe(2+) transporter called divalent cation transporter 1/divalent metal ion transporter 1 (DCT1/DMT1) (also known as natural resistance-associated macrophage protein 2). DCT1/DMT1 mRNA levels in the duodenum strongly increase in response to iron depletion. To study the mechanism of iron-dependent DCT1/DMT1 mRNA regulation, we investigated the endogenous expression of DCT1/DMT1 mRNA in various cell types. We found that only the iron responsive element (IRE)-containing form, which corresponds to one of two splice forms of DCT1/DMT1, is responsive to iron treatment and this responsiveness was cell type specific. We also examined the interaction of the putative 3'-UTR IRE with iron responsive binding proteins (IRP1 and IRP2), and found that IRP1 binds to the DCT1/DMT1-IRE with higher affinity compared to IRP2. This differential binding of IRP1 and IRP2 was also reported for the IREs of transferrin receptors, erythroid 5-aminolevulinate synthase and mitochondrial aconitase. We propose that regulation of DCT1/DMT1 mRNA by iron involves post-transcriptional regulation through the binding of IRP1 to the transporter's IRE, as well as other as yet unknown factors.

3' Untranslated Regions↗
PubMed1999

Iron transport across biologic membranes.

Iron is essential for life, but is toxic in excess. Nearly all organisms have therefore developed regulated mechanisms for efficient transport of iron into cells. This paper reviews the current understanding of iron transport, focusing on valuable lessons from studies of yeast iron transport and the discovery of the first mammalian transmembrane iron transporter.

Animals↗
PubMed1997

Cloning and characterization of a mammalian proton-coupled metal-ion transporter.

Metal ions are essential cofactors for a wealth of biological processes, including oxidative phosphorylation, gene regulation and free-radical homeostasis. Failure to maintain appropriate levels of metal ions in humans is a feature of hereditary haemochromatosis, disorders of metal-ion deficiency, and certain neurodegenerative diseases. Despite their pivotal physiological roles, however, there is no molecular information on how metal ions are actively absorbed by mammalian cells. We have now identified a new metal-ion transporter in the rat, DCT1, which has an unusually broad substrate range that includes Fe2+, Zn2+, Mn2+, Co2+, Cd2+, Cu2+, Ni2+ and Pb2+. DCT1 mediates active transport that is proton-coupled and depends on the cell membrane potential. It is a 561-amino-acid protein with 12 putative membrane-spanning domains and is ubiquitously expressed, most notably in the proximal duodenum. DCT1 is upregulated by dietary iron deficiency, and may represent a key mediator of intestinal iron absorption. DCT1 is a member of the 'natural-resistance-associated macrophage protein' (Nramp) family and thus its properties provide insight into how these proteins confer resistance to pathogens.

Amino Acid Sequence↗
PubMed1991

Characterization of phosphopeptide derived from bovine beta-casein: an inhibitor to intra-intestinal precipitation of calcium phosphate.

Casein phosphopeptide (CPP), a highly phosphorylated peptide fragment which inhibits the formation of hydroxyapatite crystal was isolated from pooled ileal contents of rats fed a semi-synthetic diet containing bovine beta-casein. The estimated amino acid sequence of the CPP was shorter than that of the trypsin-digested beta-casein but the core region consisting of consecutive bindings of phosphoserine was fully conserved. A moderate and exchangeable binding to Ca2+ of the CPP molecule well substantiates the high absorbability of calcium from milk and dairy products.

Amino Acid Sequence↗
PubMed1990

Present health situation in Tanzania.

This article discusses the present health situation in Tanzania, however, health system before independence, the colonial health system, has been the foundation on which the present health services in Tanzania are built upon. The population growth in Tanzania is high (3.2% in 1986), and projected to be 3.7% by the year 2,000. This high growth explains why it is difficult to achieve health objectives on the long term basis. Compounded to this is the economical crisis in the country. Child population in Tanzania account for about 47% of the total population in 1986. Maternal and Child Health Care services (MCHC) are discussed, with much emphasis on the child health care problems, and different programmes involved in improving child health care in the country. Problems of poor environmental sanitation are discussed including possible solutions for Tanzania. Tanzania, in this article, is urged to strengthen the existing health services in terms of staff, drugs, other supplies and equipment in order to give adequate health care to its people. Tanzania should also balance the distribution of resources between urban and rural so as to comply with the objective of the national health policy of comprehensive basic health services equitably to all within the limited available resources and to be able to reach the ultimate goal of health for all the people in the country by the year 2,000.

Child↗
PubMed1989

[Effect of Ca level on 65Zn absorption at the ligated duodenal loop of rat].

Effect of calcium concentration on Zn absorption was studied in rats. Administration of Zn solution with calcium through gastric tracts depressed markedly the levels of Zn in serum taken from portal vein. Dependency on calcium concentrations of the absorption and distribution of Ca in the body was determined using in situ administration of Zn into ligated duodenal loop of rats. Administration of Zn with high calcium solution decreased significantly the levels of Zn in serum and all the tissues compared with the administration with low and medium calcium solutions. A considerable disease in the level of Zn was observed in the liver and kidney compared with the rats administered with medium and low calcium solutions.

Animals↗