Fedorak R N, Cheeseman C I, Thomson A B, Porter V M
Department of Medicine, University of Alberta, Edmonton, Canada.
Am J Physiol. 1991 Oct;261(4 Pt 1):G585-91. doi: 10.1152/ajpgi.1991.261.4.G585.
Intestinal adaptation of glucose transport during streptozocin-induced diabetes in rats was examined using microdensitometric analysis of [3H]phlorizin binding. Results of specific phlorizin binding were correlated with measurements of maximal transport capacity, carrier affinity, villus height, and enterocyte birth rate determined by the metaphase arrest technique. Animals diabetic for 14 days (acute) and 60 days (chronic) were compared with age-matched controls. In the jejunum, adaptation occurred only in chronically diabetic rats and consisted of a 10-fold increase in the density of phlorizin binding sites in the upper villus region (i.e., that portion normally transporting glucose), while in the ileum, adaptation occurred both in acute and chronically diabetic rats and consisted of 1) a 3-fold increase in density of phlorizin binding sites in the upper villus region of acutely diabetic rats and 2) an increased density in the upper villus region as well as the recruitment of phlorizin binding sites in the mid to lower villus region (i.e., that portion not normally transporting glucose) of chronically diabetic rats. Enhancement of glucose Vmax and villus length accompanied changes in binding, whereas enterocyte birth rates were similar in each group.
采用[3H]根皮苷结合的显微密度分析方法，研究了链脲佐菌素诱导的糖尿病大鼠肠道葡萄糖转运的适应性变化。根皮苷特异性结合的结果与通过中期阻断技术测定的最大转运能力、载体亲和力、绒毛高度和肠上皮细胞出生率的测量结果相关。将糖尿病14天（急性）和60天（慢性）的动物与年龄匹配的对照组进行比较。在空肠中，适应性变化仅发生在慢性糖尿病大鼠中，表现为上绒毛区域（即正常转运葡萄糖的部分）根皮苷结合位点密度增加10倍；而在回肠中，急性和慢性糖尿病大鼠均出现适应性变化，表现为：1）急性糖尿病大鼠上绒毛区域根皮苷结合位点密度增加3倍；2）慢性糖尿病大鼠上绒毛区域密度增加，同时中下段绒毛区域（即正常不转运葡萄糖的部分）出现根皮苷结合位点募集。葡萄糖Vmax和绒毛长度的增加伴随着结合变化，而每组的肠上皮细胞出生率相似。
