scholarly journals Lead and iron absorption from rat small intestine: the effect of dietary Fe deficiency

1978 ◽  
Vol 40 (2) ◽  
pp. 253-260 ◽  
Author(s):  
I. K. Robertson ◽  
M. Worwood

1. When lead is administered in drinking-water iron-deficient rats retain more Pb than Fe-replete rats (Six & Goyer, 1972; Klauder & Petering, 1975). In the present study the relationship between the absorption of Pb and Fe was investigated.2. Adult male rats were transferred to a milk-based diet fed with or without supplementary Fe (180 mg Fe/kg as ferrous sulphate). After 7–9 d the absorption of duodenally-administered203Pb and59Fe was measured as uptake of radioactivity from the gastrointestinal tract after 90 min.59Fe absorption was increased in rats given the unsupplemented diet for 7 d and was further increased in rats kept on the diet for up to 7 weeks.203Pb absorption was not consistently increased by either short- or long-term Fe deprivation.3. Much of the203Pb in homogenates of the upper small intestine was bound to soluble protein of which up to 85% was dialysable. In contrast little59Fe was dialysable. Only a small proportion of the soluble musosal Pb was associated with ferritin during gel-filtration chromatography although203Pb precipitated together with carrier rat-liver ferritin with an antibody to rat-liver ferritin.4. There appeared to be no direct relationship between the transfer of Fe and Pb across the small intestine of the adult rat.

1994 ◽  
Vol 71 (5) ◽  
pp. 701-707 ◽  
Author(s):  
G. J. Van Den Berg ◽  
S. YU ◽  
A. G. Lemmens ◽  
A. C. Beynen

We tested the hypothesis that ascorbic acid in the diet of rats lowers the concentration of soluble Cu in the small intestine, causing a decrease in apparent Cu absorption. Male rats were fed on diets adequate in Cu (5 mg Cu/kg) without or with 10 g ascorbic acid/kg. The diet with ascorbic acid was fed for either 6 or 42 d. Ascorbic acid depressed tissue Cu concentrations after a feeding period of 42, but not after 6 d. Dietary ascorbic acid lowered apparent Cu absorption after 6, but not after 42 d. The lowering of tissue Cu concentrations after long-term ascorbic acid feeding may have increased the efficiency of Cu absorption, and thus counteracted the inhibitory effect of ascorbic acid. Dietary ascorbic acid caused a significant decrease in the Cu concentrations in the liquid phase of both the proximal and distal parts of the small intestinal lumen. This effect was due to both a decrease in the amount of Cu in the liquid digesta and an increase in the volume of the liquid phase; only the latter effect for the distal intestine was statistically significant. We conclude that ascorbic acid supplementation lowers Cu absorption by decreasing the concentration of soluble Cu in the small intestine.


1993 ◽  
Vol 294 (1) ◽  
pp. 159-165 ◽  
Author(s):  
P K Srivastava ◽  
D J Waxman

The sex-dependent expression and growth hormone (GH) regulation of rat liver glutathione S-transferase (GST) was examined using oligonucleotide probes that distinguish between closely related class Alpha (Ya1, Ya2, Yc) and class Mu (Yb1, Yb2, Yb3) GST mRNAs [Waxman, Sundseth, Srivastava and Lapenson (1992) Cancer Res. 52, 5797-5802]. Northern-blot analysis revealed that the steady-state levels of GST Ya1, Yb1 and Yb2 mRNAs are 2.5-3-fold higher in male as compared with female rat liver. In contrast, GST Yc and Ya2 mRNAs were expressed at a 2-3-fold higher level in female rat liver. Microsomal GST mRNA did not exhibit significant sex-dependent differences in rat liver. Treatment of male rats with GH by continuous infusion suppressed expression of the male-dominant GST Ya1, Yb1 and Yb2 mRNAs to levels at or below those found in female rat liver. This suppressive effect of GH was liver-specific, insofar as GH treatment did not alter kidney GST Ya1 mRNA levels. Hypophysectomy increased expression of the male-dominant GSTs, particularly in female rats (e.g. 8-fold elevation of GST Ya1 mRNA). GST Yc mRNA was increased approx. 2-fold in hypophysectomized males, indicating that this mRNA is subject to negative regulation by one or more pituitary-dependent factors. Continuous GH treatment of the hypophysectomized rats suppressed the expression of mRNA of GSTs Ya1, Yb1 and Yb2 when given as a continuous infusion, but not when given by an intermittent (twice daily) GH-injection schedule. Combination of continuous exposure to GH with thyroxine treatment resulted in a more complete suppression of GSTs Ya1, Yb1 and Yb2. In contrast, thyroxine increased the expression of GST Yc in hypophysectomized rats. These studies establish that several Alpha and Mu class GSTs are expressed in a sex-dependent fashion in adult rat liver, where they are regulated by multiple pituitary-dependent hormones through pretranslational mechanisms.


1974 ◽  
Vol 76 (3) ◽  
pp. 438-448 ◽  
Author(s):  
Richard J. Orts ◽  
Bryant Benson ◽  
Byron F. Cook

ABSTRACT Studies were made to determine if a substance other than melatonin was present in bovine pineal gland extracts which possessed properties inhibitory to some gonadotrophin-dependent reproductive parameters in rats. Bovine pineal extracts were partially purified by organic solvent extraction or by ultrafiltration and gel-filtration to exclude melatonin. When administered to rats, the extracts inhibited compensatory ovarian hypertrophy, delayed vaginal opening time and reduced the incidence of constant oestrus. Either of the melatonin-free extracts reduced significantly the concentration of serum luteinizing hormone (LH) in long-term castrate male rats. The data suggest that some substance other than melatonin present in bovine pineal glands has a modifying effect on the reproductive parameters observed probably due to its inhibitory effect on LH.


Author(s):  
M. I. Marushchak ◽  
O. M. Kopanitsa ◽  
I. Ya. Krynytska ◽  
T. Ya. Yaroshenko

Introduction. In the last decades, the carrageenans have become one of the most popular hydrocolloids in the food industry. In addition to the positive properties of hydrocolloids, researchers have established the relationship between the incidence of ulcerative colitis and the level of carrageenan consumption, which makes it considered as a potential etiological factor in the pathology of the gastrointestinal tract.The aim of the study – to determine the level of oxidative modification of proteins of the wall of the small intestine, tissues of the heart and liver of rats using 1% κ-carrageenan solution.Materials and Methods. The study was carried out on 24 white non-linear male rats. The animals of the experimental group were provided with free access to a 1.0% of carrageenan solution for 1 month. In the selected samples of the small intestine, heart and liver was evaluated the peroxidic oxidation of proteins according to the level of their oxidation modifications products using spectrophotometry at wavelengths of 370 and 430 nm.Research Results. A significant increasing of ketone dinitrophenylhydrazones levels in the small intestine wall (by 57.0%) and in the liver (by 23.0%) and, respectively, the aldehyde dinitrophenylhydrazones levels by 47.7% and 19.1%, compared with the control values (p<0.01). In this case, the peroxide oxidation, to a greater extent, was subjected to neutral proteins. It should be noted that the peroxidic oxidation of proteins in the myocardium of the rats with carrageenan consumption, recorded at a wavelength of 370 nm, exceeded the control data by 14.3% (p<0.05).Conclusions. Oral administration of a 1% carrageenan solution in experimental animals leads to statistically significant activation statistically significant activation of peroxidation of proteins in the wall of the small intestine and the liver, whereas only the growth of neutral ketone dinitrophenylhydrazones is registered in the myocardium (p<0.05).


2019 ◽  
Vol 4 (1) ◽  
pp. 21-37
Author(s):  
Junichi Kino ◽  
Norihisa Ichinohe ◽  
Masayuki Ishii ◽  
Hiromu Suzuki ◽  
Toru Mizuguchi ◽  
...  

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