Manganese Metabolism Research Articles

Effect of fluoride on tissue manganese levels in the mouse

Manganese levels were determined in liver, kidney and bone (femur) of mice subjected for 16 weeks to 0 ppm (control), 10 ppm, 25 ppm, 50 ppm, 100 ppm and 200 ppm of fluoride in drinking water. Following fluoride ingestion, manganese levels were significantly reduced in liver (in 50, 100 and 200 ppm groups) and kidney (in 100 and 200 ppm groups). On the other hand, bone manganese levels were significantly elevated following ingestion of 25 ppm or more fluoride. The results suggest that excessive fluoride ingestion disturbs manganese metabolism.

The Significant Role of Liver Lysosomes on Manganese Metabolism

The Significant Role of Liver Lysosomes on Manganese Metabolism

Iodine metabolism and tissue mineral levels in rats fed rapeseed protein concentrates supplemented with zinc

A 16-week feeding test of Tower (Brassica napus) and Span (Brassica campestris) rapeseed protein concentrates (RPC) was carried out on male and female Charles River CD (Sprague-Dawley) weanling rats. The diets contained 10% or 20% protein (N × 6.25) from each RPC and were supplemented with 150 mg zinc/kg. The control groups received a purified diet with casein or a laboratory chow diet. The results of the test diet groups did not reveal any adverse effect due to RPC on thyroid metabolism or the metabolism of zinc iron, copper, manganese, calcium, phosphorus, and magnesium. Nephrocalcinosis was observed in all female rats that were fed the test diets and the casein control diet, and therefore it could not be attributed to dietary RPC.

Effect of Dietary Manganese on Growth and Manganese Metabolism in Sheep

Three groups of five wethers were each fed ad libitum a practical type diet containing 22, 300, or 3000ppm of manganese for 8 wk. The wethers then were fistulated and killed 13h after intraruminal dosing with manganese-54. Several tissues were sampled. Average daily gains and feed/gain ratios of sheep fed diets containing 22 and 300ppm manganese were similar, but gain was lower and the ratio higher for sheep fed the diet containing 3000ppm manganese than for those fed other diets. Feed intake was approximately the same for all treatments. Increased dietary manganese increased its concentration in soft tissues and bile. There was also a decrease in the uptake and specific activity of manganese-54 in the liver with increasing dietary manganese. Concentration of copper increased and concentration of zinc decreased in liver of sheep with increasing dietary manganese.

Effect of a Purified or Corn-Skim Milk Diet on Retention and Tissue Distribution of Manganese-54 in Calves

Calves were fed a corn-skim milk or a purified diet to determine if the large differences in manganese metabolism in rats fed such diets also occurred in ruminating calves. The calf purified diet was similar to the rat purified diet but with potassium bicarbonate and sodium bicarbonate added as buffers to be suitable for ruminating calves. In contrast to the huge differences in rats, retention of manganese-54 was the same in calves fed the corn-skim milk diet as in calves fed the purified diet. It is unlikely that the minor differences in the diets caused such large differences in effects between calves and rats. A likely reason for the difference is the functional rumen in the calf. The active rumen may metabolize ingredient(s) that affect manganese absorption in the rat and, therefore, would not be in the small intestine to affect absorption by the calf.

Influence of Age on Metal Metabolism and Toxicity

The metabolism and toxicity of lead, cadmium, mercury, and manganese in the postnatal period was studied in rats. Absorption, whole body retention, and organ distribution of 203Pb, 115mCd, 203Hg, and 54Mn were determined after oral and parenteral administration of these radioisotopes. The acute oral toxicity (LD50) was determined after a single application of metal chlorides. The results obtained in sucklings show a very high intestinal absorption of all metals which is partly attributed to milk diet; a higher whole body retention, higher blood levels and a much higher accumulation in the brain; and a higher oral toxicity. These results indicate age specific differences in the pharmacokinetics of metals in sucklings. It seems reasonable to consider the early neonatal age as a critical period for metal accumulation and therefore for metal toxicity. The results are interpreted on the basis of current concepts of developmental physiology and pharmacology and suggestions for future research trends are made.

Influence of age on metal metabolism and toxicity.

The metabolism and toxicity of lead, cadmium, mercury, and manganese in the postnatal period was studied in rats. Absorption, whole body retention, and organ distribution of 203Pb, 115mCd, 203Hg, and 54Mn were determined after oral and parenteral administration of these radioisotopes. The acute oral toxicity (LD50) was determined after a single application of metal chlorides. The results obtained in sucklings show a very high intestinal absorption of all metals which is partly attributed to milk diet; a higher whole body retention, higher blood levels and a much higher accumulation in the brain; and a higher oral toxicity. These results indicate age specific differences in the pharmacokinetics of metals in sucklings. It seems reasonable to consider the early neonatal age as a critical period for metal accumulation and therefore for metal toxicity. The results are interpreted on the basis of current concepts of developmental physiology and pharmacology and suggestions for future research trends are made.

Manganese metabolism and its function.

Manganese metabolism and its function.

Effect of normal and high manganese diets on the role of bile in manganese metabolism of calves.

SUMMARY The role of bile in manganese metabolism and homeostasis was studied in Holstein bull calves fed diets containing 32 ppm manganese (normal) (control) or 1,000 ppm supplemental manganese (high-manganese) for 2 weeks before and 1 week after intravenous (IV) and duodenal S4Mn dosing. After dosing, all the bile was collected at 15 and 60 minutes, hourly to 12 hr and daily to 7 days. All calves were sacrificed 7 days after dosing to determine the tissue S4Mn distribution. High-Mn-fed calves secreted 48% of the IV S4Mn dose in bile over the 7-day period; which was 12 times that in bile of control calves. In contrast, after duodenal dosing, only a very small amount of S4Mn was secreted in bile by either control (.32%) or high-Mn-fed (.30%) calves over the 7-day period. With both methods of dosing, calves fed the high-Mn diets had a lower average S4Mn concentration in most tissues taken than calves fed the control diet. These data from IV dosing confirm earlier work that excretion and tissue distribution of injected S4Mn is very sensitive to dietary Mn. The data from duodenally-dosed calves showed that the amount of Mn absorbed is decreased by higher dietary Mn intake. In contrast to previously held theory, enterohepatic circulation of Mn apparently plays only a minor role in homeostasis of fed Mn. Manganese homeostasis in calves appears to be the result of changes both of absorption and

Manganese metabolism in cows and goats

When 54MnCl2 was incubated with fresh bovine or caprine serum for 20 h and the serum subjected to electrophoresis at pH 9.5, the 54Mn bound to transferrin and alpha2-macroglobulin in proportions which varied with the temperature of incubation and the temperature of electrophoresis. Between 0 and 37 degrees C, the higher the temperature of incubation the larger the proportion bound to transferrin and the lower the proportion bound to alpha2-macroglobulin. The temperature at which electrophoresis was performed had little effect on the proportion of 54Mn bound to transferrin, but increasing temperature reduced the proportion of 54Mn bound to alpha2-macroglobulin. Mn2+ did not bind to purified transferrin in vitro in the absence of an oxidising agent. In the presence of permanganate, Mn3+ was formed and chelated by transferrin at physiological pH. In fresh serum this oxidation step may be performed by ceruloplasmin or molecular oxygen. Mn2+ was bound reversibly to alpha2-macroglobulin but this protein played no part in the oxidation of divalent manganese and had no effect on the protein binding of trivalent manganese. Manganese in the divalent state, either free as Mn2+ or bound to alpha2-macroglobulin, is removed from blood plasma very efficiently by the liver. However, the manganic-transferrin complex normally found in circulation is not rapidly removed from plasma. The liver can remove large amounts of excess manganous manganese which it presumably excretes; the small essential fraction of the manganese absorbed is oxidised to the trivalent state and bound to transferrin.

Manganese metabolism with oral and intravenous 54Mn young calves as influenced by supplemental manganese.

Manganese metabolism with oral and intravenous 54Mn young calves as influenced by supplemental manganese.

Influence of manganese intake on metabolism of manganese and other minerals in sheep.

Influence of manganese intake on metabolism of manganese and other minerals in sheep.

Effect of Dietary Calcium and Phosphorus on 54Mn Metabolism Following Single Tracer Intraperitoneal and Oral Doses in Rats

SummaryThe effects of dietary calcium [0.1% (low) or 0.6% (normal)] and phosphorus [0.4% (normal) or 0.9% (high)] on 54Mn metabolism were determined following single ip or oral dosing in weanling rats. Rats receiving the low calcium diet excreted much more 54Mn from both ip and oral doses via feces and urine, and their tissues retained much less. Within each dietary calcium level, urinary excretion of ip administered 54Mn was far less on the high phosphorus diet. With orally administered 54Mn, high dietary phosphorus increased 54Mn tissue concentrations. These results show that low dietary calcium has a major effect on manganese metabolism at the tissue level as well as within the gut.

Diet and supplemental mineral effects on manganese metabolism in newborn calves.

Diet and supplemental mineral effects on manganese metabolism in newborn calves.

Ultrastructure of developing melanosomes in C57 Black and pallid mice

The pigment mutant pallid in the mouse was studied because its effect on inner ear development (absence of otoliths) can be phenocopied by manganese deficiency during gestation, suggesting a relationship between the gene pallid, pigmentation, and manganese metabolism. Ultrastructure was examined to compare pigment granule formation in wild-type ( C57Bl) and pallid mice at various ages in three tissues: the retinal epithelium, the inner ear epithelium, and the epidermis. Results of studies of melanosomes in the retina and skin of C57Bl mice concur with earlier reports concerning the structure of wild-type melanosomes. Pigment granule formation in the inner ear of C57Bl mice was identical to that in the retina, suggesting that these melanocytes had a common cellular origin. The protein substructure of pallid epidermal and retinal premelanosomes was similar to that of the wild type. Epidermal melanosomes were smaller than those of black mice and melanin deposition was scanty; dense melanosomes were never formed. In maturing pallid retinas, premelanosomes were unmelaninized and scarce. Melanosomes, with or without melanin, were not observed in the retinal epithelium of adult pallid animals. No immature or mature pigment granules were found in the inner ear epithelium of pallid mice. This alteration in pallid melanin formation may reduce the intracellular manganese concentration, thus resembling a dietary manganese deficiency.

Metabolism of Iron and Manganese

Metabolism of Iron and Manganese

Interrelationship of iron and manganese metabolism.

A relationship between iron and manganese metabolism has been suggested by the observation of the incorporation of manganese into the porphyrin molecule of red cells and the increased gastrointestinal absorption of manganese in iron deficiency (1, 2). The present studies were performed to determine variations in the metabolism of each of these elements induced by deficiency or overload of the other.Methods. Male albino rats (Wistar strain) weighing 200-250 g were used. The animals were fed a standard rat diet (General Biochemicals, Chagrin Falls, Ohio) except that the iron and manganese content was modified from test to test as stated. Iron absorption was measured following a test dose of 0.5 μCi of ferrous-59 Fe citrate per 0.25 mg of ferrous sulfate per 0.5 ml of distilled water, administered through a 17-gauge endoesophageal tube to rats fasted for 16 hr. Whole body radioactivity (0.8 MeV —→ ∞) was measured in a small-animal, whole-body liquid scintillation detector (Packard Armac, LaGrange, Illinois),...

Manganese and hydralazine as studied by neutron activation and radioactive Mn.

Hydralazine produces a “Lupus-like” syndrome in a few patients. This syndrome has been reproduced experimentally in the laboratory, and, circumstantially, a Mn-deficiency seemed implicated. The results of a dietary deficiency of Mn were compared to the effects of hydralazine administration. The alterations produced by dietary Mn found in mice were not duplicated by hydralazine.Studies relating hydralazine (“Apresoline,” CIBA) to manganese (Mn) metabolism have suggested that a Mn deficiency might be produced by long term administration of this drug(l). Because hydralazine can induce a syndrome similar to Systemic Lupus Erythematosus (SLE) in patients, it seemed possible that Mn deficiency might play a role in the etiology of this disease.As neutron activation analysis (NAA) has proven to be a specific and accurate technique to measure tissue concentrations of Mn, it was used to determine whether hydralazine administration might lower Mn in tissues. Although tracer techniques are not a perfect answer to the...

Essential trace metals in man: Manganese: A study in homeostasis

MANGANESE, a transitional metal with atomic number 25, has been considered essential for the normal physiological function of mammals and birds for 30 years. In spite of incontrovertible but indirect evidence of a requirement for dietary manganese, however, deficiency in man has not been recognized. There is considerable interest in the physiological and biochemical role of manganese by nutritionists, enzymologists and pathologists. The subject has been excellently reviewed on two occasions by COTZIAS$ [l, 21. There are gaps, however, in some of the basic data and, at the risk ofbeing repetitious, we have surveyed the field from biogeochemical and analytical viewpoints, as we have other trace elements, in order to answer certain questions pertinent to manganese metabolism in man. These are: (1) What are the environmental sources of manganese? (2) How good is the human homeostatic mechanism for the metal? (3) Does manganese deficiency exist in man, even if slight? (4) Do diseases caused by accumulation of manganese occur in man? (5) What is the actual daily intake of manganese by normal human beings? (6) What living organisms have homeostatic mechanisms for manganese? This report is the tenth of a series on trace elements in human beings [3-111 and represents the first on an essential one. Although there are much older data in the literature, we have attempted to present newer material not available elsewhere as well as to repeat many analyses done by others in order to arrive at our own viewpoint.

Iron, Copper, and Manganese in Germfree and Conventional Rats

The effects of the microflora on the metabolism of iron, copper, and manganese were studied using germfree and conventional rats of both sexes. Hemoglobin and hematocrit values were similar in both groups, whereas plasma iron and copper levels were slightly but significantly lower in germfree than in conventional rats. The liver of the germfree rat stored more iron than that of the conventional rat, but the spleen, kidneys, and the total body of the germfree rat contained less iron than those of the conventional animal. As expected, the iron levels in females were higher than in males in both experimental groups. The relative proportions of ferritin and hemosiderin iron in the various organs of germfree and conventional rats were comparable. The levels of copper in these organs and in the total body followed the same pattern as the iron levels in germfree and in conventional rats. In contrast with the observations on iron and copper, the concentrations of manganese in the above mentioned organs and in the total body were similar in germfree and conventional rats. The results suggest a lower rate of iron and copper metabolism and a similar rate of manganese metabolism in germfree rats as compared with conventional rats.