Katsuhiko Yokoi

Effect of dietary iron deficiency on mineral levels in tissues of rats.

AbstractTo clarify the influence of iron deficiency on mineral status, the following two synthetic diets were fed to male Wistar rats: a control diet containing 128 μg iron/g, and an iron-deficient diet containing 5.9 μg iron/g. The rats fed the iron-deficient diet showed pale red conjunctiva and less reactiveness than the rats fed the control diet. The hemoglobin concentration and hematocrit of the rats fed the irondeficient diet were markedly less than the rats fed the control diet. The changes of mineral concentrations observed in tissues of the rats fed the iron-deficient diet, as compared with the rats fed the control diet, are summarized as follows:• Iron concentrations in blood, brain, lung, heart, liver, spleen, kidney, testis, femoral muscle, and tibia decreased;• Calcium concentrations in blood and liver increased; calcium concentration in lung decreased;• Magnesium concentration in blood increased;• Copper concentrations in blood, liver, spleen and tibia increased; copper concentration in femoral muscle decreased;• Zinc concentration in blood decreased;• Manganese concentrations in brain, heart, kidney, testis, femoral muscle and tibia increased. These results suggest that iron deficiency affects mineral status (iron, calcium, magnesium, copper, zinc, and manganese) in rats.

Effect of age and dietary protein level on tissue mineral levels in female rats

Mineral (phosphorus, sulfur, potassium, calcium, magnesium, iron, zinc, copper, and manganese) concentrations were measured in plasma, and several tissues from female Wistar rats (young: 3-wk-old; mature: 6-mo-old) were fed on a dietary regimen designed to study the combined or singular effects of age and dietary protein on mineral status. Three diets, respectively, contained 5, 15, and 20% of bovine milk casein. Nephrocalcinosis chemically diagnosed by increased calcium and phosphorus in kidney was prevented in rats fed a 5% protein diet. Renal calcium and phosphorus were more accumulated in young rats than mature rats. A 5% protein diet decreased hemoglobin and blood iron. The hepatic and splenic iron was increased by a 5% protein diet in mature rats but was not altered in young rats. Mature rats had higher iron in brain, lung, heart, liver, spleen, kidney, muscle, and tibia than young rats. A 5% protein diet decreased zinc in plasma and liver. Zinc in tibia was increased with dietary protein level in young rats but was not changed in mature rats. A 5% protein diet decreased copper concentration in plasma of young rats but not in mature rats. Mature rats had higher copper in plasma, blood, brain, lung, heart, liver, spleen, and kidney than young rats. With age, manganese concentration was increased in brain but decreased in lung, heart, liver, kidney, and muscle. These results suggest that the response to dietary protein regarding mineral status varies with age.

Tissue manganese levels and liver pyruvate carboxylase activity in magnesium-deficient rats.

To investigate the manganese status in magnesium deficiency, 40 male Wistar rats, 3 wk old, were divided into two groups and fed a magnesium deficient diet or a normal synthetic diet for 2 wk. Dietary magnesium depletion decreased magnesium levels in brain, spinal cord, lung, spleen, kidney, testis, bone, blood, and plasma, while it elevated the magnesium level in liver. In magnesium-depleted rats, calcium concentration was increased in lung, liver, spleen, kidney, and testis, while it was decreased in tibia. In magnesium-depleted rats, manganese concentration was decreased in plasma and all tissues except adrenal glands and blood. Dietary magnesium depletion diminished pyruvate carboxylase (EC 6.4.1.1) activity in the crude mitochondrial fraction of liver. Positive correlation was found between the liver manganese concentration and the pyruvate carboxylase activity. In the magnesium-depleted rats, glucose was decreased while plasma lipids (triglycerides, phospholipids, and total cholesterol) were increased. These results suggest that dietary magnesium deficiency changes manganese metabolism in rats.

Effect of dietary tin deficiency on growth and mineral status in rats

To clarify the influence of dietary tin deficiency on growth and mineral status, the following two different synthetic diets were fed to male Wistar rats: group 1—a diet containing 1.99 μg tin/g; group 2—a diet containing 17 ng tin/g. The rats in group 2 showed poor growth, lowered response to sound, and alopecia, with decreased food efficiency compared with rats in group 1. The changes of mineral concentrations in tissues observed in group 2, compared with group 1, are summarized as follows: calcium concentration in lung increased; magnesium concentration in lung decreased; iron concentrations in spleen and kidney increased; iron concentration in femoral muscle decreased; zinc concentration in heart decreased; copper concentrations in heart and tibia decreased; manganese concentrations in femoral muscle and tibia decreased. These results suggest that tin may be essential for rat growth.

Iron, zinc, and copper levels in different tissues of clinically vitamin A-deficient rats

AbstractTo clarify the effect of vitamin A deficiency on iron, zinc, and copper status in different tissues, three groups of rats were fed two types of synthetic diets for 52 d. Group one, which was fed a vitamin A-deficient diet, showed severe signs of vitamin A deficiency. Groups two (fed restricted amount, pair-fed with group one), and three (fed diet ad libitum) were fed a control diet. After said period of feeding, iron, zinc, and copper were measured in different tissues. Significant changes observed when the groups were compared are summarized below:1.Iron and copper in testes were increased significantly, whereas zinc was strikingly decreased in group one when compared with the other groups;2.Copper (in lung and kidney) and iron (in the spleen) were increased significantly in group one compared with the other groups;3.In the liver, iron, zinc, and copper were significantly different between group one and group two;4.In muscle, iron was significantly higher in group one than group two;5.In tibia and blood, iron levels (but not zinc and copper) in groups one and two were significantly higher than group three. These results suggest that vitamin A deficiency affects iron, zinc, and copper status in rats.

Iron accumulation in tissues of magnesium-deficient rats with dietary iron overload.

The mineral imbalances in magnesium-deficient rats with dietary iron overload were studied. Forty-four male Wister rats were divided into six groups and fed six diets, two by three, fully crossed: magnesium adequate or deficient, and iron deficient, adequate, or excess. The concentrations of iron, magnesium, calcium, and phosphorus in tissues of the rats were measured. The results were as follows: (1) The excess iron intake reinforced the iron accumulation in liver and spleen of magnesium deficient rats; (2) The saturation of iron binding capacity was enormously elevated in the magnesium deficient rats fed excess iron; and (3) Dietary iron deprivation diminished the degree of calcium deposition in kidney of magnesium deficient rats. These results suggest that magnesium-deprived-rats have abnormal iron metabolism losing homeostatic regulation of plasma iron, and magnesium deficient rats with dietary iron overload may be used as an experimental hemochromatosis model.

A gel filtration high-performance liquid chromatographic method for determination of hepatic and renal metallothionein of rat and in comparison with the cadmium-saturation method

Metallothionein (MT) is a low-mol-wt protein. The essential trace elements copper and zinc and the potentially toxic elements, such as cadmium, can induce the synthesis of and bind to MT. The major functions of MT are related to metal metabolism. This paper reported and evaluated a new method for determination of hepatic and renal MT of rat by using high performance liquid chromatography (HPLC) with a Superdex 75 gel filtration column. The tissue was homogenized and centrifuged, then the supernatant was pretreated simply by cadmium saturation and heating before HPLC determination. The MT was completely and clearly separated from other proteins in the rat tissues in a short time, and was quantitated directly as a function of UV absorbance at 250 nm. The recovery both for hepatic and renal MT of rat were exceed 90%. The coefficient of variation was 1.3% for hepatic MT of rat and 1.7% for renal MT of rat. The detection limit was 0.265 μg for hepatic MT and 0.095 μg for renal MT of rat. The present method was compared with the traditional cadmium-saturation method for determination of hepatic and renal MT of rat. A good correlation was found in these two methods.

EFFECT OF LOW DIETARY RUBIDIUM ON PLASMA BIOCHEMICAL PARAMETERS AND MINERAL LEVELS IN RATS

The effects of low dietary rubidium on plasma biochemical parameters and mineral levels in tissues in rats were studied. Eighteen male Wistar rats, weighing about 40 g, were divided into two groups and fed the diets with or without supplemental rubidium (0.54 vs 8.12 mg/kg diet) for 11 wk. Compared to the rats fed the diet with supplemental rubidium, the animals fed the diet without rubidium supplementation had higher urea nitrogen in plasma; lower rubidium concentration in tissues; lower sodium in muscle; higher potassium in plasma, kidney and tibia, and lower potassium in testis; lower phosphorus in heart and spleen; lower calcium in spleen; higher magnesium in muscle and tibia; higher iron in muscle; lower zinc in plasma and testis; and lower copper in heart, liver, and spleen, and higher copper in kidney. These results suggest that rubidium concentration in tissues reflects rubidium intake, and that rubidium depletion affects mineral (sodium, potassium, phosphorus, calcium, magnesium, iron, zinc, and copper) status.

Determination of nonheme iron using inductively coupled plasma-atomic emission spectrometry.

A technique for the rapid and accurate estimation of nonheme iron using inductively coupled plasma-atomic emission spectrometry is described. Yttrium was used as an internal standard. An external calibration method was used. The standards were prepared in a matrix composed of 2.5N HCl in 10% (w/v) trichloroacetic acid. The supernatant and coagulum fractions of liver nonheme iron were separated by the method of Drysdale and Ramsay with minor modification (13). The data determined by this procedure was compared and found to be agreement with data determined by the method of Hallgren (12). To evaluate the iron status of rats, hemoglobin and liver nonheme iron were determined. Hemoglobin and all of the nonheme iron fractions of the rats fed an iron-deficient diet were significantly lower than those of the rats fed an iron-sufficient diet. The blood content in the liver was estimated to be 80 μL/g from the blood iron concentration, and the difference between total and nonheme iron concentration in liver.

Miniature hydride generator system for inductively coupled plasma-atomic emission spectrometry

ConclusionThe detachable miniature hydride generator presented in this work gives the analytical chemist easy access to the determination of ultratrace levels of tin and germanium using a 1.2 kW-ICP spectrometer commercially available. An improvement of the detection limits of approximately 100 times those for conventional pneumatic nebulizer-ICP-AES, has been reported in this work.