Locatto M E, Fernández M C, Abranzón H, Caferra D, Puche R C
Departamento de Ciencias Fisiológicas, Facultad de Ciencias Médicas, Rosario, Republica Argentina.
Bone Miner. 1990 Feb;8(2):119-30. doi: 10.1016/0169-6009(90)90115-v.
This paper reports an investigation designed to determine the influence of varying degrees of insulinopenia upon the calcium metabolism of actively growing, alloxan-treated rats fed diets with three levels of calcium. A significant reduction in the skeletal mass (in absolute terms) was observed one month after alloxan administration in rats fed diets with normal or high calcium contents. The impact of insulin deficiency was greater on bone collagen than on the mineral mass, as shown by the increased calcium/hydroxyproline ratio. Alloxan-treated rats showed rather increased levels of PTH which was at variance with respect to control animals and unrelated to the calcium content of the diet. In spite of the high PTH levels, diabetic rats showed significantly diminished rates of bone Ca accretion and resorption. In addition, the animals fed the diet with the normal Ca content, showed significantly reduced areas of osteocytes lacunae and hypocalcemia after 24 h of fasting. The overall information obtained indicates that, in the rat, insulin deficiency more pronouncedly affects organic matrix than mineral turnover. The diabetic state is characterized by an impaired response of bone tissue to physiological stimuli, which is attributed to defective cellular activity caused by insulin deficit. Diminished bone resorption is considered to be an adaptative response to preserve bone mass.
本文报道了一项研究，旨在确定不同程度的胰岛素缺乏对喂食三种钙水平日粮的、用四氧嘧啶处理的生长活跃大鼠钙代谢的影响。在给予四氧嘧啶一个月后，观察到喂食正常或高钙含量日粮的大鼠骨骼质量（绝对值）显著降低。钙/羟脯氨酸比值增加表明，胰岛素缺乏对骨胶原的影响比对矿物质质量的影响更大。四氧嘧啶处理的大鼠甲状旁腺激素（PTH）水平相当高，这与对照动物不同，且与日粮钙含量无关。尽管PTH水平较高，但糖尿病大鼠的骨钙沉积和吸收速率显著降低。此外，喂食正常钙含量日粮的动物在禁食24小时后，骨细胞陷窝面积和血钙水平显著降低。获得的总体信息表明，在大鼠中，胰岛素缺乏对有机基质的影响比对矿物质更新的影响更为明显。糖尿病状态的特征是骨组织对生理刺激的反应受损，这归因于胰岛素缺乏导致的细胞活性缺陷。骨吸收减少被认为是一种保护骨量的适应性反应。
