• Journal of Nutrition and Health
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• 제36권6호
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• pp.549-558
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• 2003

The purpose of this study was to determine which differences in the source of protein (soy vs casein) and isoflavones in soy protein are responsible for the differential effects of bone marks and hormones in growing female rats. Forty-two 21-day-old Sprague-Dawley female rats were randomly assigned to one of three groups, consuming casein (control group), soy protein isolate (57 mg isoflavones/100 g diet), or soy protein concentrate (about 1.2 mg isoflavones/100 g diet). All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. And bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, estrogen and calcitonin were analyzed using radioimmunoassay kits. Diet did not affect weight gain and mean food intake. Food efficiency ratio was lower in the soy protein groups. The soy isolate group had a higher ALP and osteocalcin concentration and lower crosslinks value than the casein group. Therefore, the soy isolate groups had a higher bone formation/resorption ratio than the casein group. And, the soy group had significantly higher growth hormone than the casein group. The findings of this study suggest that soy protein and isoflavones are beneficial for bone formation in growing female rats. Therefore, exposure to these soy protein and isoflavones early in life may have benefits for osteoporosis prevention.

• Journal of Nutrition and Health
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• 제38권5호
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• pp.344-351
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• 2005

The purpose of this study was to examine the impact of isoflavones on lipid concentrations and hepatic LDL receptor mRNA level in growing female rats. Twenty four rats (body weight $75\pm5g$) were randomly assigned to one of two groups, consuming control diet or isoflavones supplemented diet (57mg isoflavones/100g diet). All rats has been fed on experimental diet and deionized water ad libitum for 9 weeks. The concentration of triglyceride and total cholesterol were measured in serum and liver. Serum HDL cholesterol was measured. Hepatic LDL receptor mRNA level was tested by RT-PCR. Supplementation of isoflavones did not affect weight gain, mean food intake and food efficiency ratio. Serum total cholesterol and non-HDL cholesterol of isoflavones supplemented rats were significantly lower than those of control rats (p<0.05). But hepatic cholseterol was not influenced by supplementation of isoflavones. Hepatic LDL receptor mRNA level not significantly different between control group and isoflavones supplemented group. Therefore, isoflavones may be beneficial on serum cholesterol and non-HDL cholesterol lowering in growing female rats.

• Journal of Nutrition and Health
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• 제40권3호
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• pp.235-241
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• 2007

The aim of this study was to define an arginine effect when added to a diet. The influence of arginine supplements on bone mineral density and content were studied in young female Sprague-Dawley rats fed either an arginine supplemented diet or control diet. Twenty four rats (body weight $83{\pm}5g$) were randomly assigned to one of two groups, consuming casein or casein with supplemented arginine diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur 3, 6, and 9 weeks after feeding. The serum and urine concentrations of Ca and P were determined. Diet did not affect weight gain and mean food intake. The serum concentration of Ca and P were not changed by arginine supplementation. Urinary Ca excretion was significantly decreased by arginine supplementation. Spine BMD was significantly increased by arginine supplementation on 3 and 6 weeks after feeding. Femur BMD was significantly increased in the group of arginine supplementation on 3, 6, and 9 weeks. Rats fed the arginine-supplemented diet had better bone mineral content than did control diet rats in the experimental period. Therefore, arginine supplementation may be beneficial on spine and femur BMD increment in growing female rats. These are thought to be associated with an arginine-induced growth hormone release. The exact mechanism of this effect remains to be elucidated.

• Journal of Nutrition and Health
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• 제40권4호
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• pp.320-326
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• 2007

An important related question is whether arginine has influence bone metabolism. The effect of arginine supplements on bone markers and related hormones were studied in young female Sprague-Dawley rats fed either an arginine supplemented diet or control diet. Twenty four rats (body weight 83${\pm}$5 g) were randomly assigned to one of two groups, consuming casein or casein with supplemented arginine diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. And bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, estrogen, insulin-like growth factor-1 (IGF-1), parathyroid hormone (PTH) and calcitonin were analyzed using radioimmunoassay kits. The weight gain and mean food intake were not affected regardless of diets. The rats fed arginine-supplemented diet had not significantly different in ALP, osteocalcin, crosslinks value, PTH, estradiol, and IGF-1 compared to those fed casein diet group. The arginine-supplemented group had significantly higher growth hormone and calcitonin than casein group. This study suggests that arginine is beneficial for bone formation in growing female rats. Therefore exposure to diet which rich in arginine early in life may have benefits for bone formation and osteoporosis prevention.

• Nutritional Sciences
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• 제9권2호
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• pp.74-81
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• 2006

The present study examined the effect of soy isoflavones on lipid metabolism in growing female rats. Rats were randomly assigned to three different groups and provided experimental diets for 9 weeks. The experimental groups were classified into 1) a control group, 2) a soy protein isolate group: soy (+)) group and 3) a soy protein concentration group: soy (-)) group. Diets contained either casein or one of two soy proteins with (soy (+)) or without isoflavones (soy (-)). Serum triglyceride concentration showed no significant differences among the experimental groups. Serum total cholesterol concentration was significantly lower in both the soy (+) and soy (-) groups than in the control group and LDL-cholesterol concentration was significantly lower in the soy (+). Serum HDL-cholesterol concentration was significantly higher in the control group than in the soy protein groups but the HDL-cholesterol share rate in total cholesterol tended to be lower in the control group than in the soy protein groups, insignificant as it was. Hepatic IDL receptor mRNA level was significantly increased in the soy (+) group when compared to the other two groups to be 20% higher than the control group. In conclusion, soy protein isolate, soy protein rich with isoflavones reduced serum total cholesterol and LDL-cholesterol concentration and increased hepatic IDL receptor mRNA expression in growing female rats. Therefore, it is considered that the intake of soy isoflvones during puberty can be advantageous in terms of the long-tenn control of serum lipid.

• Journal of Community Nutrition
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• 제4권3호
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• pp.195-201
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• 2002

The purpose of this study was to examine the effects of dietary calcium supplementation and exercise on bone mineral density and bone mineral content of growing female rats. The exercise and control group were fed a diet containing 0.5% calcium and Ca supplementation group were fed a diet containing 1.0% calcium diet. The exercise group ran on a rodent treadmill (speed of 15m/min for 30 min) three days per week during the 3-week study period. Bone mineral density (BMD) and bone mineral content (BMC) of spine and femur were determined by using dual energy x-ray absorptiometry (FIXI-mus, GE Lunar Radiation Cooperation, Madison, WI, USA). The exercise group had significantly greater (6.25%) spine BMD compared to the nonexercise group and the exercise group had but not significantly greater spine BMC (7.1%) compared to nonexercisers. Femur BMD and BMC divided by the rats final body weight appears to have a higher BMD (7.5%) and BMC (4.5%) in the exercise group, which indicates that exercise had a positive influence on femur bone mineral density and bone mineral content. The supplementation of calcium did not significantly affect spine and femoral BMC and BMD for the 3 weeks experimental period. It can be concluded that when calcium intake meets the recommended, exercise is beneficial for acquisition of spine bone mineral density in young growing female rats. (J Community Nutrition 4(3) : 195∼201, 2002)

• Nutrition Research and Practice
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• 제2권2호
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• pp.68-73
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• 2008

This study was focused on whether or not isoflavones affect the increase in bone mineral density of growing females. Female Sprague-Dawley rats ($60{\pm}5\;g$) were randomly assigned to two groups and provided control diets (control group) or isoflavone-supplemented diet (IF group, 57.8 mg isoflavones/100 g diet) for 9 weeks in growing female rats. Measurements of Bone Mineral Density (BMD) and Bone Mineral Content (BMC) on the experimental animals were executed in the $3^{rd}$, $6^{th}$, $9^{th}$ weeks. In result, there was no significant difference in spine BMD between the isoflavones supplemented group and the control group. But, the IF group tended to have higher BMD than the control group in between 3 and 9 experimental weeks, and the striking difference could be shown in the $6^{th}$ week of feeding. In case of femur BMD, the effects of added isoflavones appeared in the $6^{th}$ week of feeding, and it became intensified in the $9^{th}$ week of feeding to the extent that the BMD in the IF group was significantly higher than that of the control group (p<0.05). In conclusion, isoflavone supplementation increased spine BMD per weight in the $6^{th}$ week of feeding, and affected the increase of femur BMD in the $9^{th}$ week. The result of the experiment implies that it affects positively the formation of spine and femur BMD of growing female rats. The study also suggests that the effects of isoflavone on the pattern of BMD formation might differ from the parts of bones.

• Journal of Nutrition and Health
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• 제39권4호
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• pp.338-346
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• 2006

The overall purpose of this study was to investigate the effects of level of isoflavones supplementation on bone metabolism in growing female rats. The effects of level of isoflavones supplementation on bone mineral density (BMD) and bone mineral content (BMC) were inspected in this study. Forty-five rats divided into three groups: Casein, $^1/{_2}IF$, IF. The serum and urine concentrations of calcium and phosphorus were determined. BMD and BMC were estimated by using PIXImus (GE Lunar Co, Wisconsin.) in spine and femur on 3, 6, 9 weeks after feeding. This study of results were as follows: The isoflavones supplementation level did not affect weight gain, mean food intake and food efficiency ratio. The serum concentration of calcium, phosphorus were not significantly different by different level of isoflavones supplementation. The urinary calcium and phosphorus excretion were not significantly different, too. Spine and femur BMD, BMC were not significantly increased by different level of isoflavones supplementation on 3 and 6 weeks after feeding. Spine BMD and spine BMC per weight, femur BMC per weight were significantly increased in the groups $^1/{_2}IF$ and IF at the ninth week after feeding, but there was no significant difference by different level of isoflavones supplementation. Spine BMD per weight and femur BMD per weight were significantly higher in the group of IF than in the group of Casein and $^1/{_2}IF$ at the ninth week after feeding. These results suggest that the group of IF with rich isoflavones supplementation was effective to the increase of BMD spine and femur in growing female rats, respectively.

• Journal of Nutrition and Health
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• 제36권4호
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• pp.359-367
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• 2003

The purpose of this study was to examine the impact of soy protein and soy isoflavones on bone and mineral density in young female Sprague-Dawley rats. Fifty eight rats (body Weight 75 $\pm$ 5 g) were randomly assigned to one of four groups, consuming casein, soy protein concentrate, soy protein isolate (57 mg isoflavones/100 g diet) or casein added isoflavones (57 mg isoflavones /100 g diet). All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur on 3, 6, 9 weeks after feeding. The serum and urine concentrations of Ca and P were determined. Diet did not affect weight gain and mean food intake. Food efficiency ratio was lower In soy protein groups. The serum concentration of Ca and P were not changed by soy protein and isoflavones. Urinary Ca and P excretion were not significantly different. Spine BMD was significantly increased by soy protein isolate on 3 and 6 weeks after feeding. Femur BMD was significantly increased in the groups of soy protein isolate and isoflavones adding on after 9 weeks. Therefore, soy protein with rich isoflavones may be beneficial on spine and femur BMD increasement in growing female rats.

• 한국식품영양과학회지
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• 제11권1호
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• pp.57-68
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• 1982

사료의 단백질과 에너지 수준이 흰쥐의 성장 및 체조성에 미치는 영향을 알기 위해서 생후 3주된 Sprague-Dawley계 albino rat 암수 각각 100마리에서 표준사료를 5일동안 급여한 후 암쥐는 체중이 $70{\sim}80g$되는 것으로 93마리를 선택하였다(3마리는 개시기 도체분석에 사용하였으며, 90마리는 사양실험에 사용하였음). 실험사료의 에너지 수준은 ME를 저에너지(3200kcal/kg), 중에너지(3600kcal/kg), 고에너지(4000kcal/kg)로 달리했으며, 단백질 수준은 ME 3600kcal/kg에 대해서 저단백질(15%), 중단백질(25%), 고단백질(35%)의 3수준으로 하고, 지방수준은 ME 3600kcal/kg에 대해서 저지방(10%), 중지방(20%), 고지방(40%)의 3수준으로 정하고 나머지 에너지는 전분과 포도당으로 보충한 9종의 사료처리구에 대한 사양실험, 및 도체분석 실험을 실시했던 바 얻어진 결과를 요약하면 다음과 같다. (1) 증체량은 암수 모두 저단백질 수준(13%)에서 가장 높았으며, 암쥐의 경우 증체량이 가장 큰 것은 LP-HE구(121g)였고, 숫쥐의 경우 LPME(210g)로서 사료의 에너지 수준에 따라서 암수의 최대증체량은 달랐다 이 결과에서 성장을 위해서 숫쥐는 NRC(1980) 사양 표준 에너지(3600kcal/kg)에 적합하나 암쥐는 더 많은 사료 에너지의 요구됨이 시사되었다. 8주간 성장 곡선을 보면 암수간에 상당한 차이를 보였으며 암쥐는 3주까지, 숫쥐는 5주까지 급격한 성장을 보였고, 그 이후부터는 완만한 성장율을 나타냈다. 또한 증체량에 대한 사료중 영양소 수준의 효과가 암쥐에서 보다 수쥐에서 더욱 예민하게 나타났다. 이 결과에서 사양실험에 적합한 실험동물은 암쥐보다 숫쥐가 더욱 효과적이라 생각되었다. 사료섭취량은 증체량 사이에 밀접한 관계가 있음을 나타냈다. 사료효율은 암쥐의 경우 단백질과 에너지 수준이 NRC(1980) 사양표준치에서 가장 높은 사료효율을 나타냈다. 단백질 효율은 암수 모두 저단백질 수준에서 가장 높았으며 에너지 수준은 암쥐의 경우 고에너지 수준에서, 숫쥐의 경우 중에너지 수준에서 가장 높은 단백질 효율을 나타냈다. 사료의 단백질과 에너지 수준이 흰쥐의 성장에 미치는 영향을 보면 사료효율 및 단백질 효율은 증체량에 직접적인 영향을 미친다. 증체량은 사료의 섭취량에 영향을 받기보다는 사료의 조성에 영향을 받는 것으로 생각되며 특히 에너지 수준에 따라 크게 영향을 받는다. (2) 체조성에 관하여 체수분과 체단백질은 암수 모두 사료 단백질 수준에 의해서 차이가 없었다. 체지방은 암쥐의 경우 사료 단백질과 에너지 수준이 증가할수록 뚜렷하게 증가했으나 숫쥐의 경우 단백질 및 에너지 수준에 의해서 큰 차이가 없었다. (3) 이상으로 본 실험결과를 종합하여 볼 때 암수의 성장곡선간에는 상당한 차이가 있었으며, 최대 증체량은 암쥐의 경우 단백질 수준 13%, 에너지 수준 3600kcal/kg으로 구성된 사료에서 얻어졌으며, 암수 각각 이 수준의 사료에서 또한 가장 높은 사료 효율 및 단백질 효율을 보였다. 이러한 사료의 조성은 암쥐의 경우 단백질 수준은 NRC 사양 표준치 이상에서 숫쥐의 경우 단백질과 에너지 수준이 모두 NRC 사양표준치에 일치했다.