Tsuchita H, Goto T, Shimizu T, Yonehara Y, Kuwata T
Nutrition Research Institute, Meiji Milk Products Co., Ltd., Tokyo, Japan.
J Nutr. 1996 Jan;126(1):86-93. doi: 10.1093/jn/126.1.86.
The effect of dietary Ca-bound casein phosphopeptides (CaCPP) on the bones of aged ovariectomized (OVX) rats was studied as a model for post-menopausal bone loss. Three groups of ovariectomized rats were fed a control diet or one of two experimental diets, and one group of sham-operated rats (SHAM) was fed the control diet. The experimental diets contained 0.5% Ca and 0.4% P. In one diet, CaCPP was the sole source of calcium and provided 62.5% of dietary phosphorus (CaCPP diet). In the other, Ca-free CPP provided 100% of dietary phosphorus (Ca-free CPP diet). In the control diet, CaCO3 and KH2PO4 were used. During a 17-wk feeding period, there was little change in femoral bone mineral densities (BMD) of ovariectomized rats fed CaCPP and Ca-free CPP, or in the SHAM rats fed the control diet, whereas the bone mineral densities in the control ovariectomized rats decreased with time. Some of the segmental bone mineral densities of the excised femurs from the rats fed CaCPP were significantly higher than those from the control ovariectomized rats, but the values of the Ca-free CPP group were similar to those of the control ovariectomized rats. In the Ca-free CPP group, the discrepancy in bone mineral densities obtained between in vivo results and excised specimens might have been the result of a loss in bone mass due to their significant loss in body weight. There were no significant differences in serum inorganic phosphorus, alkaline phosphatase activity, osteocalcin or 1 alpha-25-dihydroxycholecalciferol concentrations among the ovariectomized groups. In the CaCPP and Ca-free CPP groups, urinary phosphorus excretion decreased and urinary calcium excretion increased significantly with time. The inhibitory effect on bone loss in aged ovariectomized rats could be due to the effects of dietary CaCPP on phosphorus and calcium metabolism.
以饮食中钙结合酪蛋白磷酸肽（CaCPP）对老年去卵巢（OVX）大鼠骨骼的影响作为绝经后骨质流失的模型进行了研究。三组去卵巢大鼠分别喂食对照饮食或两种实验饮食之一，一组假手术大鼠（SHAM）喂食对照饮食。实验饮食含有0.5%的钙和0.4%的磷。在一种饮食中，CaCPP是钙的唯一来源，并提供饮食中62.5%的磷（CaCPP饮食）。在另一种饮食中，无钙CPP提供饮食中100%的磷（无钙CPP饮食）。在对照饮食中，使用碳酸钙和磷酸二氢钾。在17周的喂养期内，喂食CaCPP和无钙CPP的去卵巢大鼠以及喂食对照饮食的SHAM大鼠的股骨骨矿物质密度（BMD）变化不大，而对照去卵巢大鼠的骨矿物质密度随时间下降。喂食CaCPP的大鼠切除股骨的一些节段骨矿物质密度显著高于对照去卵巢大鼠，但无钙CPP组的值与对照去卵巢大鼠相似。在无钙CPP组中，体内结果和切除标本之间获得的骨矿物质密度差异可能是由于体重显著减轻导致骨量损失的结果。去卵巢组之间血清无机磷、碱性磷酸酶活性、骨钙素或1α-25-二羟胆钙化醇浓度没有显著差异。在CaCPP和无钙CPP组中，尿磷排泄随时间显著减少，尿钙排泄随时间显著增加。对老年去卵巢大鼠骨质流失的抑制作用可能归因于饮食中CaCPP对磷和钙代谢的影响。
