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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the activity and kinetic parameters of microvillous enzymes in intestinal villous cells and the concentration of the secretory component (SC) of p-immunoglobulin A in subcellular fractions of crypt cells in 35-day-old rats made iron deficient from birth and in controls. The aim of the study is to investigate the biochemical basis for the decreased activity of brush-border disaccharidases observed in growing animals with chronic iron deficiency. In rats made iron deficient, the specific (per unit protein) and the total (per total intestinal length) activities of sucrase, lactase, maltase, aminopeptidase, and diamine oxidase were decreased from -17 to -66% compared with the activities measured in the controls. The lower activity of sucrase in the brush-border membrane of the iron-deficient rats was associated with much slower enzyme synthesis rate than in control animals. Km of sucrase was identical in both iron-deficient rats and controls, but the maximum velocity of enzyme reaction was reduced proportionally to the enzymatic activity, indicating a lesser amount of enzyme rather than an inactivation. Electron microscopy of epithelial villous cells from iron-deficient rats revealed a marked rarefaction of secretory granules (transport vesicles) without apparent change in the morphology of the brush-border membrane or of cellular organelles. In villus and crypt cells isolated from the jejunum of iron-deficient rats, SC concentration was reduced to a level about half that of the controls. When SC concentration was measured in subcellular fractions of crypt cells, SC content in each fraction was two to three times lower in iron-deprived rats than in controls without evidence of accumulation of the protein at a given subcellular level.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alteration of intracellular synthesis of surface membrane glycoproteins in small intestine of iron-deficient rats. 378 40

Newborn rats born to iron deficient mothers (IDM) were found to have significantly lower hemoglobin, sucrase, lactase and maltase levels compared to control newborn rats. Rats born to IDM and nursed by IDM, when sacrificed at 21 days of age, had statistically significantly lower hemoglobin, serum iron, sucrase, lactase and maltase levels compared to control rats. Rats born to IDM, but nursed by iron sufficient mothers (ISM) and sacrificed at 21 days of age, had hemoglobin, serum iron and sucrase levels compared to control rats whereas lactase and maltase were not corrected by 21 days of nursing by ISM. Rats burn to IDM and nursed by either IDM or ISM for 21 days were given intramuscular iron dextran and placed on iron sufficient diet (ISD) for 7 days. These animals experienced correction of the hemoglobin, serum iron, sucrase and maltase levels compared to control rats, whereas intestinal lactase was not corrected by 7 days of ISD and intramuscular iron. Rats born to ISM, nursed by IDM and sacrificed on day 21 had significantly lower hemoglobin, serum iron and intestinal lactase levels compared to control rats. Rats both to ISM and nursed by IDM were given intramuscular iron dextran on day 21 and placed on an ISD from day 21-28. These animals had a return in hemoglobin, serum iron, sucrase and maltase levels comparable to control rats. Rats born to and nursed by ISM and maintained on an iron deficient diet from day 21-84 had significantly lower hemoglobin, serum iron, sucrase, lactase and maltase levels compared to control rats. Rats born to and nursed by ISM, maintained on iron deficient diet from day 21-84, and then given intramuscular iron dextran on day 84 and maintained on an ISD until day 92, experienced correction of the hemoglobin, serum iron and lactase levels compared to control rats. Intramuscular iron and 7 days of ISD did not correct the sucrase and maltase levels in these rats. Lactose tolerance tests in iron deficient rats showed flat curves compared to controls. After iron treatment, lactose tolerance curves returned to control values. Iron deficiency in rats in utero, during the nursing and postweaning period causes, in addition to anemia, a reduction in jejunal disaccharidase activity because of an alteration in the enzymes of the brush border membrane. Varying degrees of reduction and response of certain disaccharidases to iron treatment are dependent on the time of iron deprivation in relationship to the intra-uterine and postnatal development of the digestive and absorptive functions in the small intestine. Alterations in the levels of disaccharidases demonstrated in this paper represents another aspect of the spectrum of biochemical effects of iron deficiency.
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PMID:Disaccharidase levels in iron deficient rats at birth and during the nursing and postweaning periods: response to iron treatment. 707 2

Duodenal mucosa showed normal morphology, interepithelial lymphocytes, alkaline phosphatase, and sucrase in a girl with growth retardation and iron deficiency, but normal absorption of lactose and xylose after two years of abnormal stools. Mucosal lactase was low. Fourteen months later mucosal damage consistent with coeliac disease was evident, and gluten intolerance was subsequently confirmed by gluten challenge. It is probable that, in some children, the mucosal lesion occurs very gradually, so that at an early stage with normal morphology, suppression of lactase activity and possibly interference with iron absorption may be the only abnormalities.
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PMID:Early or pre-coeliac mucosa: development of gluten enteropathy. 746 78

Iron-deficiency anemia is the nutritional deficiency most frequently occurring throughout the world, which manifests as a complex systemic disease involving all cells, affecting enzyme activities and modifying protein synthesis. In view of these considerations, the objective of the present study was to determine the effects of iron-deficiency anemia on disaccharidases and on the epithelial morphokinetics of the jejunal mucosa. Newly weaned male Wistar rats were divided into 4 groups of 10 animals each: C6w received a standard ration containing 36 mg elemental iron per kg ration for 6 weeks; E6w received an iron-poor ration (5-8 mg/kg ration) for 6 weeks; C10w received an iron-rich ration (36 mg/kg ration) for 10 weeks; E10w received an iron-poor ration for 6 weeks and then an iron-rich ration (36 mg/kg) for an additional 4 weeks. Jejunal fragments were used to measure disaccharidase content and to study cell proliferation. The following results were obtained: 1) a significant reduction (P < 0.001) of animal weight, hemoglobin (Hb), serum iron and total iron-binding capacity (TIBC) in group E6w as compared to C6w; reversal of the alterations in Hb, serum iron and TIBC with iron repletion (E10w = C10w); animal weights continued to be significantly different in groups E10w and C10w. 2) Sucrase and maltase levels were unchanged; total and specific lactase levels were significantly lower in group E6w and this reduction was reversed by iron repletion (E10w = C10w). 3) The cell proliferation parameters did not differ between groups. On the basis of these results, we conclude that lactase production was influenced by iron deficiency and that this fact was not related to changes in cell population and proliferation in the intestinal mucosa.
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PMID:Disaccharidase levels in normal epithelium of the small intestine of rats with iron-deficiency anemia. 936 8

Disaccharidases are important digestive enzymes whose activities can be reduced by iron deficiency. We hypothesise that this is due to reduced gene expression, either by impairment to enterocyte differentiation or by iron-sensitive mechanisms that regulate mRNA levels in enterocytes. Iron-deficient Wistar rats were generated by dietary means. The enzyme activities and kinetics of sucrase and lactase were tested as well as the activity of intestinal alkaline phosphatase (IAP)-II because it is unrelated to carbohydrate digestion. mRNA levels of beta-actin, sucrase, lactase, and the associated transcription factors pancreatic duodenal homeobox (PDX)-1, caudal-related homeobox (CDX)-2, GATA-binding protein (GATA)-4, and hepatocyte nuclear factor (HNF)-1 were measured by real-time PCR. Spatial patterns of protein and gene expression were assessed by immunofluorescence and in situ hybridization, respectively. It was found that iron-deficient rats had significantly lower sucrase (19.5% lower) and lactase (56.8% lower) but not IAP-II activity than control rats. Kinetic properties of both enzymes remained unchanged from controls, suggesting a decrease in the quantity of enzyme present. Sucrase and lactase mRNA levels were reduced by 44.5% and 67.9%, respectively, by iron deficiency, suggesting that enzyme activity is controlled primarily by gene expression. Iron deficiency did not affect the pattern of protein and gene expression along the crypt to villus axis. Expression of PDX-1, a repressor of sucrase and lactase promoters, was 4.5-fold higher in iron deficiency, whereas CDX-2, GATA-4, and HNF-1 levels were not significantly different. These data suggest that decreases in sucrase and lactase activities result from a reduction in gene expression, following from increased levels of the transcriptional repressor PDX-1.
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PMID:Decreased sucrase and lactase activity in iron deficiency is accompanied by reduced gene expression and upregulation of the transcriptional repressor PDX-1. 1608 62