Bar A, Cohen A, Eisner U, Risenfeld G, Hurwitz S
J Nutr. 1978 Aug;108(8):1322-8. doi: 10.1093/jn/108.8.1322.
Changes in intestinal calcium absorption, calcium deposition into egg shell, and intestinal, renal and uterine calcium-binding protein (CaBP) in laying hens were related to changes in 25 hydroxycholecalciferol-1-hydroxylase activity (1-hydroxylase), or to the supplementation of 1alpha-hydroxycholecalciferol (1alpha-OH-CC). The onset of egg production resulted in an increased kidney 1-hydroxylase activity and intestinal and uterine CaBP. Renal concentrations of CaBP remained unchanged. Intestinal calcium and phosphorus absorption, during the period of egg shell formation, and duodenal calcium-binding protein (CaBP), were higher in 1alpha-OH-CC-fed than in cholecalciferol-fed hens. Renal or uterine CaBP and calcium deposition into the egg shell did not fluctuate with the vitamin D source or concentration. 1alpha-OH-CC injection into non-laying Nicarbazinfed hens resulted in an increase in intestinal but not renal or uterine CaBP concentrations. It is suggested that (a) CaBP in various organs responded independently to the same stimuli; and (b) calcium deposition into egg shell and uterine CaBP level are not related to kidney 1-hydroxylase activity or concentration of 1,25 dihydroxycholecalciferol.
蛋鸡肠道钙吸收、钙在蛋壳中的沉积以及肠道、肾脏和子宫钙结合蛋白（CaBP）的变化与25-羟胆钙化醇-1-羟化酶活性（1-羟化酶）的变化或1α-羟胆钙化醇（1α-OH-CC）的补充有关。产蛋开始导致肾脏1-羟化酶活性以及肠道和子宫CaBP增加。肾脏中CaBP的浓度保持不变。在蛋壳形成期间，1α-OH-CC喂养的母鸡肠道钙和磷的吸收以及十二指肠钙结合蛋白（CaBP）高于胆钙化醇喂养的母鸡。肾脏或子宫CaBP以及钙在蛋壳中的沉积不会随维生素D来源或浓度而波动。向不产蛋的尼卡巴嗪喂养的母鸡注射1α-OH-CC会导致肠道CaBP浓度增加，但不会导致肾脏或子宫CaBP浓度增加。研究表明：（a）不同器官中的CaBP对相同刺激的反应是独立的；（b）钙在蛋壳中的沉积和子宫CaBP水平与肾脏1-羟化酶活性或1,25-二羟胆钙化醇的浓度无关。
