• Journal of Nutrition and Health
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• v.30 no.4
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• pp.394-405
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• 1997

Endogenous zinc is important for maintaining zinc homeostasis because the size of endogenous zinc pool is almost 3-4 times bigger than that of dietary zinc. The purpose of this study was to examine the phytate effect on the reabsorption of endogenous zinc and the additional Ca effect on the phytate effect. Rats were fed a casein-based diet with added sodium phytate containing either high(1.6%) or low(0.8%) Ca concentrations for 4 weeks to reduce the body zinc pool. After the depletion period, $^{65}$ Zn was given by intraperitoneal injection to label the endogenous zinc pool. Rats were then assigned into phytate or non-phytate group within the same Ca group. feces were collected for 2 weeks of the initial collection period and 1 week after dietary crossover. The ratios of excreted fecal $^{65}$ Zn radioactivity of phytate group non-phytate group were determined as a measure of the phytate effect on the endogenous zinc. Mean fecal $^{65}$ Zn radioactivity was higher in the phytate group than in the non-phytate group during the entire 3 weeks of the collection period in the low Ca group, and during the initial collection period in the high Ca group(p <0.0001). This study showed an adverse phytate effect on endogenous zinc at both high and low dietary Ca levels. Elevated dietary Ca levels showed a synergistic effect on the phytate effect on endogenous zinc(p <0.05). These results imply greater phytate effect on zinc homeostasis rather than on zinc bioavailability through complexing with the endogenous zinc which is larger portion than the dietary zinc on zinc homeostasis.

• Journal of Nutrition and Health
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• v.23 no.4
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• pp.237-247
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• 1990

This study was to investigate the effect of zinc supplementation on serum cholesterol concentration of young women. Thirty healthy students were divided into Zn and placebo groups, and were orally given with zinc(50mg/day, 220mg as ZnSO4·7H2O) or placebo for 2 month (June 9-August 7, 1988). Changes of plasma zinc, serum total cholesterol, HDL-cholesterol (HDL-C), LDL-cholesterol(LDL-C) and total lipid were analyzed from the initiation to 1 month after the end of zinc supplementation at monthly interval. Plasma zinc, serum LDL-C content and LDL-C/HDL-C were significantly increased by zinc supplementation. Serum total cholesterol content tended to be increased by zinc supplementation but was not significantly different between the two groups. Serum HDL-C content was significantly decreased by zinc supplementation. Serum total lipid content was not different between the two groups during experimental period. Thus, in this study considering the effect of zinc supplementation on serum cholesterol concentration, we conclude that the effect of zinc supplementation on coronary heart disease may be negative.

• Preventive Nutrition and Food Science
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• v.2 no.1
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• pp.35-41
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• 1997

The pancreas is an important organ in the maintenance of zinc homeostasis. Endogenous zinc is con-tinuously secreted via pancreatic exocrine fluid or to a lesser extent in bile. Much of the endogenous secretion must be reabsorbed to sustain zinc homeostasis. The objective of this study was to estimate the relative size of the pancreatic/biliary zinc pool in comparision to the dietary zinc intake, and to study the effect of the phytate and calcium on the zinc homeostasis using a rat model. At the termination of the experiment, pan-creatic/biliary fluid was collected from the rats. Both radioactivity and total zinc were measured and the relative size of the pancreatic/biliary zinc pool was estimated. To determine the effect of phytate and calcium on zinc homeostsis, dietary zinc intake, the amount of zinc in pancreatic.biliary fluid and fecal zinc excretion were measured. The flow rate of pancreatic/biliary fluid, as corrected for tubing constriction, gives the corrected zinc concentration in the pancreatic/biliary fluid was 2.2 times higher than dietary zinc intake. To maintain zinc homeostasis, zinc absorption/reabsorption was very efficient in the current model; 76%, 88% of absorption/reabsorption for low calcium group and high calcium group 81% for phytate group and non-phytate group, respectively.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.406-414
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• 1997

It has been known that dietary phytate decreases the absorption of body zinc pool which is composed of the dietary and endogenous zinc in the body. The purpose of this study was to examine the effect of phytate on the absorption of total bodyzinc in Zn-depleted rats. Rats were Zn-depleted with either low(0.8%) or high(1.6%) Ca diet containing sodium phytate for 4 weeks. After zinc depletion, rats were assigned into phytate or non-phytate dietary groups within each low-or high-Ca dietary group. ant feces were collected for 2 weeks of the initial collection and 1 week after dietary crossover, during which the phytate and the non-phytate diet was switched over within the same Ca group. The content of Zn and Ca measured by atomic absorption spectrophotometer and phytate content was analyzed. food intake was higher in the high Ca group than in the low Ca group(p <0.0001), and was also higher in the non-phytate group than in the phytate group(p <0.0001). Food intake and phytate level affected body weight gain in rats(p <0.0001). Zinc excretion in the total feces was higher in the phytate group than in the non-phytate group at both low and high Ca level(p <0.0001), except during the crossover collection period in high Ca group. Calcium, however, didn't show any synergistic effect on phytate effect(p <0.05). This study showed that phytate decreased the absorption of total body zinc at both low and high Ca levels in Zn-depleted rats. A large portion of total body zinc originated from the endogenous zinc pool in these rats. The results of the present study showed the same effect of phytate on the endogenous zinc in Zn-depleted rats as in a previous study, confirming that phytate adversely affects zinc bioavailability, especially under marginal and poor zinc nutrition.

• Korean Journal of Community Nutrition
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• v.3 no.3
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• pp.389-396
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• 1998

This study was intended to examine the zinc status and effect of zinc supplementation on the zinc nutritional status of the elderly living in the Ulsan area. The zinc intake of 207 subjects(male 97, female 110) was measured by a 24-hour dietary recall and food frequency method. Biochemical analysis were conducted from blood and urine samples to evaluate the changes of zinc nutriture with zinc supplementation. The average dietary zinc intake of subjects was $7.7\pm{2.8mg}$ for male and $7.5\pm{2.6mg}$ for female, which were 51.3% and 62.3% of Korean RDA respectively. The first source of zinc was cereal and grain(36%), and the second was eggs and milk group(27%). After 8 weeks of zinc supplementation, the serum zinc content was significantly increased(p<0.01), although the serum copper content was not significantly decrease. Serum HDL- cholesterol level was not significantly decreased with zinc supplementation. Serum alkaline phosphatase(ALP) activity and urinary zinc excretion were significantly increased(p<0.05). The urinary Zn/Cr was not significantly increased. It is suggested from the results that the daily zinc supplementation can be effective to improve zinc nutriture.

• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.2
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• pp.11-22
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• 1998

For the purpose of preparation of monodispersed spherical zinc oxide fine particles, an experimental research on the preparation of zinc oxide particles from zinc salts solutions by high temperature precipitation reaction was performed. Zinc oxide particles were precipitated from all the precipitation solutions tested if the precipitation temperature was higher than 60$^{\circ}$. As the precipitation temperature Increased until 80$^{\circ}$, the average particle diameter of zinc oxide particles decreased and the narrower particle size distribution were obtained. Spherical zinc oxide fine particles with relatively narrow particle size distribution were precipitated from the ZnSO$_4$ solutions with NaOH as precipitant. Final pH of precipitation solution had an effect on the amount of zinc oxide precipitated, but had no effect on the their particle size or size distribution.

• Nuclear Engineering and Technology
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• v.11 no.1
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• pp.47-54
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• 1979

A field experiment has been carried out to evaluate the residual effect of zinc fertilizers by rice plant grown under flooded conditions in the field. The results obtained are summarized as fellows ; Residual effect of zinc fertilizers on yields of rough and hulled grains showed slight increases. Effect of zinc application methods on yields of the grains were shown that zinc mixed treatment could be more effectively utilized than treatment of zinc on the soil surface. In case of levels of zinc application, 5 kg zinc per hectare represented high yields of the grains than those obtained from 10kg and 20kg zinc placement per hectare respectively. Regarding the form of zinc fertilizers, the urea-zinc complex showed less effective on yields of the grains than did the zinc sulfate. This phenomenon was consistent with the previous result. Yields of total zinc in rice plant grown on the rice straw added soils (Treatment No. 2 and 8) and the urea-zinc complex treated soil were increased markedly as compared to those data obtained from the previous year. The percentage of zinc derived from fertilizer decreased largely as compared to that of the first year crop. The yield of fertilizer zinc in rice plant decreased slightly in the most zinc treatments but in the case of treatments of zinc mixed with the straw added soil and the urea-zinc complex increased reversely as compared to the previous results. The mixed application of zinc with soil showed higher yield of fertilizer zinc than the soil surface placement. Approximately from 4.6 to 24.3 per cent of zinc taken up by rice plants were derived from the fertilizer zinc. Zinc fertilizer use efficiency ranged from 0.213 to 0.584 per cent when 5 kg zinc per hectare applied.

• Journal of Veterinary Clinics
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• v.35 no.5
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• pp.195-199
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• 2018

Zinc is necessary for normal functions in the immune system. The objective of the study is to examine the effect of zinc on the chemotactic activity of porcine peripheral blood polymorphonuclear cells (PMNs). A modified Boyden chamber was used to determine the directional migration distance of PMNs. Various concentrations of zinc showed no chemotactic activity to PMNs. However, culture supernatant from peripheral blood mononuclear cells (PBMCs) treated with zinc remarkably increased the chemotactic activity of PMNs when compared with culture supernatant from PBMCs treated without zinc. Culture supernatant from PBMCs treated without zinc also increased the migration distance of PMNs relative to vehicle control (medium alone). Increasing effect in chemotactic activity of PMNs by culture supernatant from PBMCs treated with zinc was inhibited by treatment of porcine anti-interleukin (IL)-8 polyclonal antibody (pAb). This effect was not affected by heat treatment ($4-85^{\circ}C$). This corresponded with heat stable physical characteristics of IL-8. These results suggest that zinc can upregulate the chemotaxis of PMNs, which is primary mediated by IL-8 chemotactic factor released from PBMCs treated with zinc.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.6
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• pp.687-699
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• 2005

In order to investigate the effect of dietary zinc and phytic acid levels on protein metabolism in rats, male rats of Sprague-Dawley strains weighing approximately $60\~74g$ were fed different diets which contained 0, 0.35 and $1.05\%$ phytic acid each at 3 levels of zinc(0, 30 and 1,500 ppm zinc) for 28 days. Result obtained in this experiment are summarized as follows; 1. Body weight gait food consumption food efficiency ratio and protein efficiency ratio were lower in the rats fed zinc deficient diet(0 ppm zinc) than in those consuming 30 or 1,500 ppm dietary zinc, and the additional effect of phytic acid were not observed in all of then 2. Liver weight was lower in the rats fed 30 ppm zinc diet than in those fed 0 or 1,500 ppm-zinc diet but kidney and spleen weights were lower in the rats fed zinc deficient diet than in those fed 30 or 1,500 ppm-zinc diet Among organs measured only the liver appeared to be influenced by dietary phytic acid: the more the dietary phytic acid, the more the weight of liver, 3. Fecal nitrogen was decreased in the rats fed zinc deficient diet compared with those fed 30 or 1,500 ppm dietary zinc. Urinary nitrogen was increased in the rats fed $1.05\%$ dietary phytic acid compared with those fed 0.35 or $0\%$ dietary phytic acid Nitrogen retention of rat was influenced by neither dietary zinc nor phytic acid. 4. Urea nitrogen was decreased with increasing dietary zinc levels, and creatinine and uric acid levels were increased with increasing dietary zinc concentration or with additional quantity of phytic acid. Uric acid appeared to be influenced by zinc x phytic acid interaction; especially, the presence of phytic acid in the 30 ppm-zinc diet had significant effect on uric acid content. 5. Hemoglobin concentrations and hematocrit ratio were higher in the rats fed 30 ppm dietary zinc than in those fed 0 or 1,500 ppm-zinc diet Serum zinc concentration was increased with increasing dietary zinc levels. The content of total protein albumin and BUN and the ratio of albumin to globulin in serum, and protein content in liver were influenced by neither dietary zinc nor phytic acid.

• Nutrition Research and Practice
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• v.4 no.5
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• pp.356-361
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• 2010

Zinc is an essential trace element required for bone formation, however not much has been clarified yet for its role in osteoblast. We hypothesized that zinc would increase osteogenetic function in osteoblasts. To test this, we investigated whether zinc treatment enhances bone formation by stimulating osteoblast proliferation, bone marker protein alkaline phosphatase activity and collagen synthesis in osteoblastic MC3T3-E1 cells. MC3T3-E1 cells were cultured and treated with various concentrations of zinc (0, 1, 3, 15, 25 uM) along with a normal osteogenic medium (OSM) as control for 1, 5, 10 days. As measured by MTT assay for mitochondrial metabolic activity, cell proliferation was stimulated even at low zinc treatment (1-3 ${\mu}M$) compared to OSM, and it was stimulated in a zinc concentration-dependent manner during 5 and 10 days, with the most pronounced effect at 15 and 25 uM Zn. Cellular (synthesized) alkaline phosphatase (ALP) activity was increased in a zinc concentration-dependent manner, so did medium (secreted) ALP activity. Cellular collagen concentration was increased by zinc as time went by, therefore with the maximum zinc stimulatory effect in 10 days, and medium collagen concentration showed the same pattern even on 1 and 5 day. This zinc stimulatory effect of collagen synthesis was observed in cell matrix collagen staining. The study results imply that zinc can increase osteogenic effect by stimulating cell proliferation, ALP activity and collagen synthesis in osteoblastic cells.