Changes in Carboxypeptidase A, Dipeptidase and Na+/K+ ATPase Activities in the Intestine of Rats Orally Exposed to Different Doses of Cadmium

Eriyamremu, George E.; Asagba, Samuel Ogheneovo; Onyeneke, E. C.; Adaikpoh, M. A.

doi:10.1007/s10534-004-1202-3

Cited by 30 publications

(20 citation statements)

References 19 publications

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“…The observed decrease in contractile response in the Cd-administered rats is in good agreement with previous studies in smooth intestinal muscle [7,29]. The atropine inhibition is clearly present in both experimental and control animals.…”

Section: Discussionsupporting

confidence: 92%

Cadmium Reduces Contractile Responses of Rat Duodenum, In Vitro

Koç

Koçak

Akçıl

2008

Biol Trace Elem Res

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The present study focuses on the effects of cadmium in drinking water on rat duodenum contractility, in vitro. Two experimental groups (n = 10 each) were administered with 15 ppm cadmium chloride in their drinking water for 1 and 2 months, respectively. Two separate groups (n = 10 each) were maintained in similar conditions but received no cadmium and acted as controls. After the experimental period, the duodenal segment responses were measured by means of an isotonic transducer. The average peak amplitude of acetylcholine-induced contractions was significantly decreased in both cadmium-treated groups. Incubation of duodena from the cadmium-free controls with atropine or in a calcium-free medium resulted in reduced contractility that was undistinguishable from that of the cadmium-treated rats. Cadmium reduces the contractile response apparently by directly or indirectly decreasing cellular calcium influx.

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Section: Discussionsupporting

confidence: 92%

Cadmium Reduces Contractile Responses of Rat Duodenum, In Vitro

Koç

Koçak

Akçıl

2008

Biol Trace Elem Res

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“…In many ER stress-related diseases, including cadmium intoxication, abnormalities in ion-pumping activity of the Na,K-ATPase have been reported (61)(62)(63). However, there is a lack of information regarding effects of the ER stress on maturation, quality control, and degradation of the enzyme.…”

Section: Discussionmentioning

confidence: 99%

Diverse Pathways for Maturation of the Na,K-ATPase β1 and β2 Subunits in the Endoplasmic Reticulum of Madin-Darby Canine Kidney Cells

Tokhtaeva

Sachs

Vagin

2010

Journal of Biological Chemistry

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Proper folding of the Na,K-ATPase ␤ subunits followed by assembly with the ␣ subunits is necessary for their export from the endoplasmic reticulum (ER). Here we examine roles of the ER lectin chaperone, calnexin, and non-lectin chaperone, BiP, in folding and quality control of the ␤ 1 and ␤ 2 subunits in Madin-Darby canine kidney cells. Short term prevention of glycan-calnexin interactions by castanospermine slightly increases ER retention of ␤ 1 , suggesting minor involvement of calnexin in subunit folding. However, both prolonged incubation with castanospermine and removal of N-glycosylation sites do not affect the ␣ 1 -assembly or trafficking of ␤ 1 but increase the amount of the ␤ 1 -bound BiP, showing that BiP can compensate for calnexin in assisting ␤ 1 folding. In contrast to ␤ 1 , prevention of either N-glycosylation or glycan-calnexin interactions abolishes the ␣ 1 -assembly and export of ␤ 2 from the ER despite increased ␤ 2 -BiP binding. Mutations in the ␣ 1 -interacting regions of ␤ 1 and ␤ 2 subunits impair ␣ 1 assembly but do not affect folding of the ␤ subunits tested by their sensitivity to trypsin. At the same time, these mutations increase the amount of ␤-bound BiP but not of ␤-bound calnexin and increase ER retention of both ␤-isoforms. BiP, therefore, prevents the ER export of folded but ␣ 1 -unassembled ␤ subunits. These ␣ 1 -unassembled ␤ subunits are degraded faster than ␣ 1 -bound ␤ subunits, preventing ER overload. In conclusion, folding of the ␤ 1 and ␤ 2 subunits is assisted predominantly by BiP and calnexin, respectively. Folded ␤ 1 and ␤ 2 either assemble with ␣ 1 or bind BiP. The ␣ 1 -bound ␤ subunits traffic to the Golgi, whereas BiP-bound ␤ subunits are retained and degraded in the ER.Recent studies have shown that N-glycans of newly synthesized glycoproteins serve as recognition tags for the ER 2 lectin chaperones, which assist maturation of these proteins (1-3). Calnexin and UGGT1 (UDP-glucose glycoprotein glucosyltransferase 1) are the two key components of the ER lectin quality control systems. Calnexin binding facilitates co-translational protein folding with help from folding enzymes (1, 3).Many proteins complete their folding program at this point. The properly folded molecules are then exported to the Golgi, whereas terminally misfolded conformers are retained and later degraded. However, other proteins require additional rounds of calnexin-assisted folding to achieve their native conformation. UGGT1 acts as a conformation sensor by reglucosylating incompletely folded glycoproteins and targeting them to additional cycles of calnexin-assisted refolding (1, 3). VIP36 (vesicular integral membrane protein) and ERGIC53 (ER-Golgi intermediate compartment) assist export of the properly folded glycoproteins from the ER to the Golgi. Other lectins, including EDEM-1 (ER degradation enhancer, mannosidase ␣-like 1), target terminally misfolded glycoproteins to ER-associated degradation (4).N-Glycans are added co-translationally to the asparagines of N-glycosylation sites of nascent gl...

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“…Moreover, Cd dietary contamination with enriched food can impair the efficiency of the metal to penetrate the intestinal epithelium of fish species (Pierron et al 2008). Indeed, a decrease in protein digestibility and an inhibition of intestinal enzymes due to Cd was observed in different phyla (Eriyamremu et al 2005;Moza et al 1995).…”

Section: Bioaccumulationmentioning

confidence: 99%

Impact of cadmium on aquatic bird Cairina moschata

et al. 2009

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The impact on palmiped Cairina moschata of two levels of dietary cadmium (Cd) contamination (C1: 1 mg kg(-1) and C10: 10 mg kg(-1)) was investigated on liver gene expression by real-time PCR. Genes involved in mitochondrial metabolism, in antioxidant defences, detoxification and in DNA damage repair were studied. Metallothionein (MT) protein levels and Cd bioaccumulation were also investigated in liver, kidneys and muscle. Male ducks were subjected to three periods of exposure: 10, 20 and 40 days. Cd was mainly bioaccumulated in kidneys first and in liver. The concentrations in liver and kidneys appeared to reach a stable level at 20 days of contamination even if the concentrations in muscle still increased. Cd triggered the enhancement of mitochondrial metabolism, the establishment of antioxidant defences (superoxide dismutase Mn and Cu/Zn; catalase) and of DNA repair from 20 days of contamination. Discrepancies were observed in liver between MT protein levels and MT gene up-regulation. MT gene expression appeared to be a late hour biomarker.

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Changes in Carboxypeptidase A, Dipeptidase and Na+/K+ ATPase Activities in the Intestine of Rats Orally Exposed to Different Doses of Cadmium

Cited by 30 publications

References 19 publications

Cadmium Reduces Contractile Responses of Rat Duodenum, In Vitro

Cadmium Reduces Contractile Responses of Rat Duodenum, In Vitro

Diverse Pathways for Maturation of the Na,K-ATPase β1 and β2 Subunits in the Endoplasmic Reticulum of Madin-Darby Canine Kidney Cells

Impact of cadmium on aquatic bird Cairina moschata

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