欲探討飲食中鈣、磷比例與蛋白質含量對老年雌鼠骨骼可能造成的影響。以84隻12個月大多產之Long-Evans老鼠在一半施以卵巢切除，另一半施予假手術一個月後，任意取樣分配到以NRC建議量( 8.4% )和3倍NRC建議量( 25.2% )等二種蛋白質含量與以NRC :NRC( 0.5%: 0.4%)，1/3NRC : NRC和1/3NRC : 3NRC等3種鈣 : 磷所交叉配成的6種飼料組內。連續餵飼8個月並進行鈣、磷攝取、排遺、排泄與骨骼組織狀態的分析。綜合整個實驗結果，顯示:1.低鈣正常磷量和低鈣高磷量飲食對於老鼠體內鈣磷的代謝有不良的影響，尤其是低鈣高磷的飲食，對於老年老鼠的骨質流失有密切關係。2高蛋白飼料似乎對鈣、磷的代謝和骨骼生理衡定亦可能有不良的影響。雖然本實驗並未有明確顯示，但從低鈣高磷高蛋白飲食造成老年老風骨骼密度降低，厚度藏薄，灰分、鈣、磷含量減少的結果來看，攝取低鈣高磷且高蛋白的飲食明顯的有促使老鼠骨質疏失加速的現象。3.推論到目前國人飲食型態，似宜加以修正，建議宜多攝取奶類食品，並避免過的肉類和豆製品以減少骨質流失之嚴重性。 The effect of dietary Ca/P ratio and protein level on aged femal rats was studied. Before the experiment, half of the 84 multifertiled femal Long-Evans rats, 12 months age,has been ovariectomized in order not to produce estrogen and the other half has been sham-operated to eliminate the variation of operation. Each overiectomized or sham-operated rats were divided randomly into 6 groups. Two protein levels (NRC and 3NRC)and three Ca/P ratios (NRC: NRC,1/3NRC:NRC and 1/3NRC:3NRC) were interlaced into 6 different diets and fed to the ovariectomized and sham-opemted rat groups. The animals were fed for 8 mondts. Blood, urine, feces md bone were determined in the study.Results demonstrated that (1) Low calcium and hig phosphorus diet enhanced bone collagen breakdown and increased urinary hydroxyproline. High protein with normal Ca/P mtio diet caused similar results. (2) When phosphorus intake was raised, calcium excretion in feces increased. Adding protein to the low calcium high phosphorus diet,the results indicated that urinary calcium excretion decreased but the calcium balance still in negative status. (3) Results of blood analysis showed that serum calcium, phosphorus and hydroxyproline concentrations were not sigzificantly effected by the diets. (4)The analysis results of femur density, dry fat-free bone weigt, bone ash content, cortical thickness and mineral contents have shown that long term consumption of low calcium,high phosphorus and high protein diet would promoted the rate of bone loss. The low calcium md hig phosphorus intake also reduced femur breaking load and cortical thickness markedly. (5) Femur cross section showed that aging was accompanied with bone loss, but low calcium and high phosphorus diet induced bone loss more severely.Inaeasing protein level in dets did not effect bone resorption apparently. (6) The ovariectomizabon of rats had no concem with the rat's calcium and phosphorus metabolism and bone compositions.The conclusion of this experiment were that low calcium and high phosphorus diet could effect badly on calcium metabolism of aged female rats and could induce bone loss obviously. The effect of hig protein diet on calcium and phosphorus metabolism was not clear. But if high protein diet were taken together with low calcium and high phosphorus,it would enhance bone loss severely.
