Nyomba B L, Bouillon R, De Moor P
Endocrinology. 1984 Jul;115(1):191-7. doi: 10.1210/endo-115-1-191.
The influence of vitamin D status on insulin secretion and glucose tolerance was studied by a longitudinal design in the rabbit. Intravenous glucose tolerance tests were performed in Dutch rabbits (n = 12) before and after nutritional vitamin D deficiency, characterized by an absence of circulating 25-hydroxyvitamin D3, a 50% decrease in 1,25-dihydroxyvitamin D3, and a 16% decrease in serum calcium concentrations. Glucose-induced insulin secretion was reduced by 41% as early as 2 months after the start of the vitamin D-deficient diet and was associated with an impairment of glucose tolerance. An iv calcium infusion restored the serum calcium concentration of the vitamin D-deficient rabbits (n = 5), but did not improve glucose-mediated insulin secretion. When these animals received a single ip injection of 100 ng 1,25-dihydroxyvitamin D3 10 h before the glucose test, their insulin responses significantly increased. Supplementation with 25-hydroxyvitamin D3 for 2 weeks in another group of rabbits (n = 4) resulted in marked improvement in glucose-stimulated insulin release and glucose tolerance. These results show that vitamin D affects glucose-induced insulin secretion by a mechanism that involves more than its regulating action on serum calcium concentration.
采用纵向研究设计，在兔身上研究了维生素D状态对胰岛素分泌和糖耐量的影响。对荷兰兔（n = 12）在营养性维生素D缺乏前后进行静脉葡萄糖耐量试验，其特征为循环中的25-羟基维生素D3缺失、1,25-二羟基维生素D3降低50%以及血清钙浓度降低16%。早在维生素D缺乏饮食开始2个月后，葡萄糖诱导的胰岛素分泌就减少了41%，并且与糖耐量受损有关。静脉注射钙剂可恢复维生素D缺乏兔（n = 5）的血清钙浓度，但并未改善葡萄糖介导的胰岛素分泌。当这些动物在葡萄糖试验前10小时单次腹腔注射100 ng 1,25-二羟基维生素D3时，它们的胰岛素反应显著增加。在另一组兔（n = 4）中补充25-羟基维生素D3 2周，导致葡萄糖刺激的胰岛素释放和糖耐量显著改善。这些结果表明，维生素D影响葡萄糖诱导的胰岛素分泌的机制不仅仅涉及其对血清钙浓度的调节作用。
