摘要
目的：建立同位素稀释技术测定粪中内源性钙和钙的真正吸收率的方法。方法：３２只生长期雄性ＳＤ大鼠肌肉注射４５Ｃａ，每日记录进食量并分别收集粪便和尿样。整个实验期间饲喂含钙（碳酸钙形式）０．４３％的半合成饲料。在４５Ｃａ注射后的第６（１组）、９（２组）、１２（３组）和１５日（４组）各处死一组（８只）动物，分别测定粪便、尿、血浆、肝脏、肾、脾、睾丸、胰、小肠、注射端及非注射端大腿肌肉、脑、皮毛及股骨等组织中４５Ｃａ活性和钙含量，并对粪中排泄的４５Ｃａ活性进行动态观察。结果：４５Ｃａ注射一周后，粪及尿中４５Ｃａ的排出趋于稳定。比较不同组织的比活性、粪４５Ｃａ比活性与组织的比活性之比，选出血浆、肌肉、肝、脾作为参比组织分别计算内源性粪钙，得到几乎一致的结果：内源性粪钙占总粪钙的１６％，钙的真吸收率为８５％。结论：同位素稀释技术可用于测定粪中内源性钙，在肌注４５Ｃａ至少一周后的粪便可用于内源性粪钙的测定，血浆是最适宜的参比组织。
Objective: A balance study was conducted to clarify the methodological conditions for determination of endogenous fecal excretion and the true absorption of calcium by isotope dilution technique in rats. Method: 32 growing male Sprague Dawley rats were injected intramuscularly with 45 Ca. During the experiment all rats were fed semisynthetic diet containing 0.43% Ca as CaCO 3. The daily intake was recorded and feces and urine were collected. At day 6,9,12 and 15 after 45 Ca injection eight animals were killed respectively. Both 45 Ca activity and calcium contents in feces, urine, plasma and tissues were determined. Results: Within 7 days from 45 Ca injection the excretion of 45 Ca from feces and urine fluctuated, while one week later they were stable. The specific 45 Ca activity of tissues, urine and feces declined and from day 9 after 45 Ca injection the changes in specific activity was proportional to that of feces in the case of plasma, muscle, liver and spleen. The estimates of endogenous fecal Ca excretion based on plasma, muscle, liver, and spleen as reference sources were similar among tissues and constant with respect to time for day 9,12 and 15 after the 45 Ca injection. The most precise estimates were found in the case of plasma (endogenous fecal Ca: 16% of total fecal Ca; true absorption: 85% of Ca intake). Conclusion: The endogenous fecal Ca can be estimated by the isotope dilution method. The onset of fecal 45 Ca monitoring should be at least one week. Plasma is the most suitable reference source.
出处
《营养学报》
CAS
CSCD
北大核心
1998年第4期460-465,共6页
Acta Nutrimenta Sinica
