Decrease In Zinc Concentration Research Articles

Effect of zinc deficiency on zinc concentrations in various regions of the pig brain: Particular sensitivity of the cerebellum

The effect of nutritional zinc deficiency on the zinc concentrations of various brain regions was studied in the pig. Only the cerebellum showed a statistically significant decrease in zinc concentration suggesting that the cerebellum is particularly sensitive to zinc depletion.

The effect of ethylmercury on fetal development and some essential metals levels in fetuses and pregnant female rats

Ethylmercuric chloride (EtHg), at the dose of 2.5 mg Hg/kg, was administered by gavage every other day to pregnant rats from d 6 to 20 of gestation. On the 21st day of gestation, females were sacrificed to allow the evaluation of embryotoxicity and take the material for analytical determinations. Copper, zinc, iron, and calcium were determined by AAS in liver, kidneys, brain, intestines of fetal and pregnant female rats, as well as in maternal spleen, whole blood, placenta, and fetal carcass.Ethylmercury caused a decrease of the body weight gain during gestation and diminution of relative liver weight of intoxicated females. This compound also induced fetotoxic effects, evidenced by slight diminution of the length as well as the weight of fetuses.It was found that the effect of EtHg on the levels of endogenous metals is different in females and fetuses. In pregnant females, EtHg administration resulted in a significant increase of copper levels in kidneys, liver, and spleen: and in the decrease of zinc concentration in the kidneys, but an increase in placenta and blood compared with pregnant controls. EtHg induced slight decrease of iron concentration in kidneys and intestinal wall of pregnant females. The concentrations of iron in liver and kidney and of zinc in whole blood and liver were lower in control pregnant rats than those in control non-pregnant females. In fetuses of EtHg-exposed mothers, increases in kidney zinc and liver calcium levels were found, whereas tissue copper and iron concentrations were the same as in controls.

Decreased Zinc Concentration Does Not Lead to Atrophy of Rat Oral Epithelium

While most organs of young zinc-deficient rats atrophy, oral surface epithelia either convert from ortho- to parakeratosis with increased rates of proliferation and synthesis (e.g., buccal epithelium) or show no changes (e.g., palate). To test the possibility that oral epithelia sequester zinc, weanling rats were fed a zinc-deficient diet for 27 d, and zinc concentrations were assayed in buccal and palatal epithelium. Testis, duodenum, thymus, kidney, and submandibular and sublingual glands were assayed for comparison. In controls, zinc levels in the two epithelia were higher than in all other tissues except testis. Experimental epithelia showed no sequestering of zinc in the zinc-deficient state. After 27 d, experimental oral epithelium levels were 50% of controls. A marked deficit occurred in testis also; the other organs showed moderate or no reductions. The results show that loss of a major fraction of zinc occurs in tissues with inherently high zinc levels. It is evident that this loss does not interfere with the increased metabolic and proliferative performance in buccal epithelium. The mechanism by which oral epithelia, although losing half their zinc, are spared from the atrophic effects of zinc deficiency remains to be elucidated.

Factors affecting the distribution of cadmium, copper and lead and their effect upon yield and zinc content in bush beans (Phaseolus vulgaris L.)

Concentrations of Cd, Pb and Cu in the roots, stems and leaves of bulgarian bush beans (Phaseolus vulgaris L.) were determined for plants grown in various soils of increasing levels of contamination of these metals. Most of each heavy metal absorbed by plants was retained in roots. Concentrations of Cd, Pb and Cu in roots increased in response to soil concentrations, whereas, in stems, only Cd and Pb concentrations increased and Cu concentration was relatively constant. It is thought that Cu transport to the stele was metabolically controlled, whereas Cd and Pb reached the stem by leakage across non suberised areas of the endodermis. Uptake of heavy metals was associated with a decrease in zinc content in plants and a decrease in yield. By regression analysis decrease in both zinc content and plant yield could be best related to Cd content in stems. Possible reasons for these effects are discussed.

Hypozincemia in patients with malignant melanoma

In patients with malignant melanoma a decreased zinc content in the serum was observed, and our previous studies had demonstrated an increased urinary zinc excretion in these patients. These results support our hypothesis of association of zinc with melanin structures. The significant redistribution of zinc in malignant melanoma is suggested for monitoring of this disease.

Zinc metabolism in testicular feminization and surgical cryptorchid testes in rats

Rats with testicular feminization (Tfm) had been reported to have a testis specific zinc deficiency. In this report it is demonstrated that this organ specific zinc deficiency was not corrected by intraperitoneal zinc administration. Normal littermates on the other hand showed a positive testicular response to zinc administration. The increased testicular zinc level in control animals returned to normal 1 week after the zinc treatment probably due to the fast turnover of this element in the testis. Not only surgically induced cryptorchidism but also surgical cryptorchidism and epididymodeferentectomy (to simulate Tfm conditions in normal adult rats) caused a drastic reduction in testicular zinc level. Unlike in Tfm rats, however, the decrease in zinc content in operated animals was not accompanied by a corresponding decrease in alkaline phosphatase activity. Zinc concentration and alkaline phosphatase activity in plasma or other organs were not affected by the surgical procedure. The testicular copper content in the operated animals was higher than that of the unoperated controls.

Zinc deficiency: a reversible complication of uremia

Subnormal plasma zinc levels and decreased zinc concentration in hair and leucocytes as well as increased plasma ammonia and ribonuclease activity in dialyzed and nondialyzed uremic patients indicate that zinc metabolism is abnormal in uremia and is not corrected by dialysis. The effect of oral supplementation with zinc acetate (12 patients) or placebo (12 patients) on the above biochemical parameters in hemodialysis patients was determined as a part of a double-blind study. The zinc-supplemented, but not the placebo, group demonstrated significant increases in mean (+/- SD), plasma zinc (80 +/- 9 to 110 +/- 14, micrograms/dl), leucocyte zinc (56 +/- 13 to 1098 +/- 18, micrograms/10(10) cells), hair zinc (140 +/- 12 to 190 +/- 16 micrograms/g), and decreases in plasma ammonia (76 +/- 10 to 40 +/- 6 micrograms/dl) and plasma ribonuclease activity (1.49 +/- 0.08 to 0.78 +/- 0.10, OD/min/ml). Abnormalities of taste and sexual function improved significantly in patients receiving zinc but not in those on placebo therapy. These improvements in biochemical as well as clinical parameters confirm and extend our earlier observations of improvement in taste and sexual function after zinc supplementation. Together, they suggest that zinc deficiency is a complicating feature of uremia and can be corrected by oral zinc supplementation.

Tissue zinc levels as an index of body zinc status.

Dietary depletion of zinc was found to result in a 30% decrease in the total body zinc content of experimental rats when compared with control animals. In the depleted animals there was no decrease in the zinc content of hair, skin, heart or three different skeletal muscles although the levels in plasma, liver, bone, and testes were significantly reduced. The analysis of tissues from three patients suffering from disturbance of zinc metabolism suggest that man reacts to zinc deficiency in a similar way. These findings indicate that for a simple screening test of zinc status, analysis of the plasma zinc concentration remains the single most useful measurement.

Concentrations of lead, cadmium, and zinc in human heart muscle and aorta after acute myocardial infarction.

Zinc, lead, and cadmium were measured in the myocardium (left and right ventricles) and aorta of 14 women and 12 men who had died from acute myocardial infarction (MI), and of 12 control women and 15 control men who had died of acute trauma. Mineral content of the necrotic areas of the MI patients was also determined. There was little significant correlation with age, and sex could not be shown to influence the cation concentrations. Significantly larger concentrations of lead and cadmium were observed in the right ventricle of women controls. In the four populations, significantly higher zinc concentrations were found in the left ventricle. Lead and cadmium levels in aortas were consistently higher than those in left ventricles, whereas zinc levels were always lower. The lead content in the ventricles and aorta of MI victims was consistently greater than for control subjects, though the difference was not significant. However, in the necrotic area, a significant decrease in zinc concentration was noted. These results are discussed and compared with other results published previously. It is concluded that studies in this area must be continued as there are still many uncertainties.

Zinc absorption from composite meals II. Influence of the main protein source

The absorption of zinc in man from composite meals of conventional foods with various main protein sources was measured with a radionuclide technique. The meals were extrinsically labeled with 65Zn and the absorption of zinc was determined from a measurement of the whole-body retention of the isotope about 2 weeks after ingestion of the labeled meal. The meals consisted of a meat patty made from either chicken, beef, or soybeans, and included potatoes, tomatoes, and white bread. For meals based on animal protein a positive correlation was found between zinc absorption and zinc content. When 25% of the animal protein in the chicken meal was replaced by defatted soy flour neither the zinc content nor zinc absorption were significantly influenced. The same substitution in a beef meal resulted in a decrease in zinc content and also a lower zinc absorption. The absorption from a soybean meal did not differ from an animal protein meal with the same zinc content. Lower zinc absorption was found when the calcium content of a soybean meal was increased by the addition of milk. For this study, the total zinc content of the meal was the most important factor influencing the amount of zinc absorbed.

Testicular atrophy induced by phthalic acid esters: Effect on testosterone and zinc concentrations

Induction of testicular atrophy by phthalic acid (PA) and six of its esters (PAEs) were compared in male Wistar rats. Dietary administration of dibutyl (DBP), di- iso-butyl (DIBP), or di-2-ethylhexyl phthalate (DEHP) induced severe atrophy of the testes. Additionally, high testosterone and low zinc concentrations in the testes were found in DBP-, DIBP-, or DEHP-treated rats. On the other hand, dimethyl and diethyl phthalate decreased testosterone concentrations in the testes whereas zinc concentration in the testes was not changed. Di- n-octyl phthalate decreased zinc concentration, but the testosterone concentration in the testes was not changed. Testicular atrophy induced by PAEs may develop when high testosterone concentrations in the testes, and low zinc concentrations in the testes and liver occur simultaneously.

Observations of the concentration of zinc and iron in tissues of vitamin B6-deficient germ-free rats.

The transition of zinc and iron metabolism in vitamin B6 deficiency was investigated using germ-free and conventional rats. In contrast to previous reports, a decrease in zinc content was not observed in the liver, pancreas, kindney, spleen, lung or testes of vitamin B6-deficient conventional and germ-free rats, but we found an increase in zinc content in the kidney of conventional rats and in the liver and spleen of germ-free rats. Vitamin B6-deficient conventional and germ-free rats retained more iron in their tissues than the control animals did, except for the spleen of germ-free rats. The deposit of iron was more evident in vitamin B6-deficient germ-free rats than in vitamin B6-deficient conventional rats, and is possibly proportional to the degree of vitamin B6 deficiency. It is possible that the deposit of iron in the organs had some influence on metabolic disorders in vitamin B6-deficient rats.

Dose-related alterations in growth and mineral disposition by chronic oral cadmium administration in the male rat

The effect of cadmium (1, 10, or 100 ppm) administered to male rats in drinking water for 13 weeks on body weight and mineral disposition (Cd, Mg, P, and Zn) in several body tissue was examined. Most alterations observed in these parameters occured only at the 100 ppm dose of Cd. Terminal body weight was decreased . by 10% in rats ingesting Cd at 100 ppm resulting from decreased food intake since weight gain/food consumption ration was the same for all treatment groups. In serum, cadmium ingestion resulted in an inhibition of alkaline phosphatase activity at all concentrations and phosphorous was elevated only in animals receiving 100 ppm Cd. No changes were observed in Ca in urea. In bone, Cd decreased zinc content, increased Ca content, but did not influence bone ash, Mg or P and roentgenorgraphic examination revealed no bone abnormalities. In both liver and kidney, cadmium ingestion did not influence intestinal absorption of Ca, Mg, P, or Zn or the renal excretion of Ca, P, or urea. The results of this study indicate that alterations in body weight and tissue mineral disposition resulting from chronic Cd ingestion are dose-related.

Experimental zinc deficiency in humans.

The effects of a mild zinc-deficient state in humans were studied. Four male volunteers received restricted zinc intake for several weeks under strict metabolic conditions. As a result of dietary zinc restriction, a decrease in zinc concentration of plasma, erythrocytes, leukocytes, and urine was observed. Changes in the activities of zinc-dependent enzymes in the plasma such as alkaline phosphatase and ribonuclease were also related to the dietary zinc status. An adverse effect of zinc restriction on total protein, total collagen, ribonucleic acid, and the activity of deoxythymidine kinase (a zinc-dependent enzyme) in the sponge connective tissue of the two volunteers in whom this test was done was noted. During the zinc restriction period, the ammonia level in the plasma was elevated. Weight loss occurred in all subjects as a result of dietary zinc restriction. Inasmuch as the zinc-deficient state was mild, this study provides a basis for developing diagnostic criteria for zinc deficiency in humans.

Relation between zinc and iron and peroxidation of lipids in liver homogenate in CaEDTA-treated rats

Rats were administered CaEDTA at 6 mmoles/kg/24 hr either by continuous iv infusion for various periods of time up to 48 hr or by ip injection (twice daily) for 14 days. The urinary excretion pattern for zinc, iron, and copper was compared with the content of these metals in the liver. The formation of malondialdehyde (MA) and the profile of total fatty acids was studied in the liver as an index of the capacity to peroxidize unsaturated fatty acid. The urinary excretion of zinc in rats infused iv with CaEDTA reached a maximum within 3 hr, then steadily declined. By contrast, the urinary excretion of iron continuously increased during the period of infusion. Still, total zinc excretion exceeded iron excretion 10-fold over the 48-hr period. A significant decrease in the zinc content of liver occurred 2 hr after the start of infusion and was only half that of controls after 48-hr infusion. The content of iron in the liver did not change. A significant increase of copper occurred in the liver in spite of the fact that enhanced urinary excretion could account for 15% depletion of total body stores. The formation of MA by the liver was significantly enhanced in rats infused with CaEDTA for 2 hr; infusion with CaEDTA for 48 hr resulted in abolishing the capacity of the liver to produce MA. Addition of iron to liver homogenate reestablished its capacity to produce MA. A similar pattern of metal content in the liver was measured for rats chronically treated with CaEDTA; zinc significantly decreased with no change in iron. However, the capacity of the liver to produce MA was enhanced. These data, supported by changes in the profile of fatty acids, favor the view that a decrease in zinc content with no change in biologically active iron content enhances lipid peroxidation by the liver. Chelation of iron in the liver with time during the constant iv infusion of CaEDTA, presumably through the formation of ternary iron complexes in situ, prevents lipid peroxidation.

Studies on Mg, B, and Zn deficiencies in acid ‘Wilder’ soil of California

A greenhouse study of some aspects of infertility of an acid soil of California, namely the ‘Wilder’ soil, was undertaken. Experiments with white-rooted radish showed that the soil when limed to near neutrality with CaCO3 indicated deficiencies of boron and magnesium. When sweet corn was used as a test crop, zinc deficiency was exposed in limed soil. The plant tissue tests and morphological observations corroborated this. The apparent decrease in zinc content in sweet corn in presence of the added phosphate was taken to be a dilution effect.

Relation of Zinc and Calcium Concentrations in Hair to Zinc Nutrition in Rats ,

Zinc concentration decreased substantially in newly grown hair of nearly all rats depleted of zinc by being fed diets containing approximately 2 ppm zinc. Lowered zinc concentrations in hair occurred with significantly greater frequency than decreased growth rates. Some rats with markedly decreased zinc concentrations in hair, however, maintained growth rates that did not differ from those of pair-fed controls consuming the same diet but supplemented with 20 ppm of zinc. It is concluded that zinc concentrations in hair are dependent upon zinc intake, but that they do not necessarily reflect the severity of the metabolic effects of zinc deficiency as manifested by impaired growth rates. Lowered concentrations of zinc in the hair of zinc-depleted rats were associated with elevated concentrations of calcium.

Effects of vitamin B6 and B1 deficiencies and restricted caloric intake on tissue zinc levels.

Studies from this laboratory have suggested that there is a decreased availability of insulin in vitamin B6 deficient rats (1). Although the role of zinc on insulin metabolism has never been determined, associations of zinc and insulin have been reported for more than 30 years. Recent in vitro studies (2,3) using isolated epididymal adipose tissue have clearly shown that zinc in concentrations in the range of those observed in human and rat plasma and higher inhibit insulin activity. Hsu (4) has reported that vitamin B6 deficiency in rats results in decreased zinc content of plasma, liver, pancreas, and heart tissues. Work in this laboratory using a different experimental protocol appeared in disagreement with Hsu's conclusions. This report contains a study of the effects of vitamin B6 deficiency on tissue zinc concentrations. Since some pyridoxal enzymes are magnesium dependent and it has been shown that magnesium supplementation of vitamin B6 deficient rations for rats prevents at least in part some effects of vitamin B6 deficiency, [protects against calcium oxalate urolithiasis, increases urinary citrate and decreases xanthurenic acid excretion (5)] the effects of vitamin B6 deficiency on tissue Mg levels were also investigated. To partially determine how specific the effects observed were, studies of the effects of thiamine deficiency and restricted feeding on zinc tissue levels and the effects of restricted feeding and vitamin B6 deficiency on potassium tissue levels were also under taken. Experimental. Weanling male Charles River CD rats were used in these studies. They were fed semipurified diets containing in percent: casein, 25; sucrose, 70.7; corn oil, 9; cod liver oil, 1; salts IV (6), 4; and choline, 0.3. Eight mg of riboflavin, 40 mg of niacin, 20 mg of calcium pantothenate, 1 mg of folic acid, 1 mg of menadione, 0.2 of biotin, 0.05 mg of vitamin B12 and when used 4 mg of thiamine hydrochloride, and 4 mg of pyridoxine hydrochloride were added to each kilogram of diet. The basal diet contained 40 mg of magnesium and 1.4 mg of zinc/100 gm.

Production of Zinc Deficiency in the Squirrel Monkey (Saimiri sciureus)

Zinc deficiency was produced in the squirrel monkey by feeding a low zinc diet containing casein as the protein source. The casein was rendered low in zinc by a procedure combining isoelectric precipitation and treatment with disodium ethylenediaminetetraacetic acid (Na2 EDTA). The diet was tested in two experimental trials, in which eleven, weanling, male squirrel monkeys were fed the diet for periods up to 352 days and were compared with eleven control monkeys fed the same diet supplemented with 15 µg zinc/g. Growth in monkeys fed the low zinc diet was retarded; the animals became unkempt in appearance, and some showed varying degrees of hair loss. Hair samples obtained on days 22–23 of feeding showed decreased zinc concentrations. Red cell volumes and red cell hemoglobin concentrations, determined serially until days 56–57, were normal. At killing, reduced zinc concentrations were found in the heart, spleen, liver, and pancreas. In the adrenal, zinc concentration was increased, while in bone it was normal. Three monkeys fed the low zinc diet for more than 130 days showed decreased concentrations of serum albumin and zinc.

Effects of different levels of zinc and phosphorus on the growth of subterranean clover (Trifolium subterraneum L.)

Four water culture experiments are described in which the effects of the addition of all combinations of graduated amounts of phosphorus and zinc on the growth of subterranean clover were studied.In the first experiment, the variety Dwalganup was used, and in the other experiments the varieties Clare and Edenhope. Varietal differences in the symptoms of zinc deficiency are described. Phosphorus toxicity symptoms occurred in the variety Clare but not in Edenhope. The effects of increases in zinc or phosphorus level, or both, on growth of top + root (T + R) and on percentage top are described. A highly significant variety x phosphorus interaction effect on T + R was recorded at adequate zinc levels, which indicated that the phosphorus requirement of Edenhope was considerably greater than that of Clare. By contrast, tolerance to high levels of zinc in the substrate was greater in Clare than in Edenhope. In the presence of added phosphate, the initial T + R response to small, but still insufficient, additions of zinc to the substrate occurred in root growth more than in top growth, whereas when a level of zinc adequate for normal growth was supplied, top growth of the plants benefited more than root growth. Highly significant zinc x phosphorus interaction effects on T + R occurred. No relationship existed between zinc concentration and the occurrence of zinc deficiency symptoms. The critical zinc level was not a point of narrow range, but included a wide range of values, depending on the age of the plants and the phosphate level. The depression in T + R induced by high phosphate when the zinc level was insufficient was not due to a decrease in zinc concentration resulting from the high phosphate treatment, but such plants gave a high value for the phosphorus/zinc ratio. The results suggest that zinc is essential to phosphate utilization by the plant. Evidence of redistribution of phosphorus from tops to roots, and of decreases in the total amount of phosphorus in phosphorus-deficient plants, was obtained in one experiment between days 27 and 60.