Chertow B S, Driscoll H K, Blaner W S, Meda P, Cordle M B, Matthews K A
Medical Service, VA Medical Center, Huntington, West Virginia.
Pancreas. 1994 Jul;9(4):475-84. doi: 10.1097/00006676-199407000-00010.
To determine whether vitamin A is involved in pancreatic alpha cell function, we tested for (a) effects of vitamin A deficiency on glucagon release from perifused islets and perfused pancreases, and (b) the presence of cytosolic retinol-binding proteins (CRBP) and retinoic acid-binding proteins (CRABP), in the glucagon-secreting alpha cell line, ln-R1-G9. Arginine 19 mM plus glucose 2.8 mM-stimulated glucagon secretion was markedly impaired in islets and pancreases of vitamin A-deficient rats or rats that had at some time been cycled through vitamin A deficiency (ever A-def) despite repletion with retinoids for 2-4 weeks. Insulin secretion was impaired likewise. Repletion starting early in the development of vitamin A deficiency and for a longer period of time (18 or 60 days) did not restore glucagon secretion, but did normalize insulin secretion. CRBP and CRABP were present in ln-R1-G9 cells. We conclude that (a) vitamin A deficiency is associated with a defect in glucagon secretion; (b) The defect in secretion occurs early in the course of vitamin A deficiency; (c) The defect persists despite repletion; and (d) The requirement of vitamin A for secretion and the presence of CRBP and CRABP in glucagon-secreting cells support a physiologic role for vitamin A at the alpha cell level.
为了确定维生素A是否参与胰腺α细胞功能，我们进行了以下测试：(a) 维生素A缺乏对经外周灌注的胰岛和灌注胰腺中胰高血糖素释放的影响，以及 (b) 在分泌胰高血糖素的α细胞系ln-R1-G9中细胞溶质视黄醇结合蛋白 (CRBP) 和视黄酸结合蛋白 (CRABP) 的存在情况。尽管用类视黄醇补充2 - 4周，但维生素A缺乏的大鼠或曾经历过维生素A缺乏循环（曾经维生素A缺乏）的大鼠的胰岛和胰腺中，19 mM精氨酸加2.8 mM葡萄糖刺激的胰高血糖素分泌明显受损。胰岛素分泌同样受损。在维生素A缺乏发展早期开始补充且持续较长时间（18或60天）并不能恢复胰高血糖素分泌，但能使胰岛素分泌正常化。ln-R1-G9细胞中存在CRBP和CRABP。我们得出以下结论：(a) 维生素A缺乏与胰高血糖素分泌缺陷有关；(b) 分泌缺陷在维生素A缺乏过程早期出现；(c) 尽管补充后缺陷仍然存在；(d) 维生素A对分泌的需求以及在分泌胰高血糖素的细胞中存在CRBP和CRABP支持了维生素A在α细胞水平的生理作用。
