class="enumerated" style="list-style-type:decimal">In chickens, low Na+ diets markedly decrease the hexose transport in the rectal segment of the large intestine; transport in the ileum shows a lower, but significant reduction and transport in the jejunum is unaffected. These effects involve both apical (SGLT1) and basolateral (GLUT2) hexose transporters.The role of the renin-angiotensin-aldosterone axis (RAAS) in the epithelial response to Na+ intake was studied in chickens fed high-NaCl (HS) and low-NaCl (LS) diets. The Vmax of α-methyl-D-glucoside and D-glucose were determined in vesicles from the brush-border (BBMVs) and basolateral (BLMVs) membranes, respectively. The binding of phlorizin to BBMV and cytochalasin B to BLMV were used as indicators of the abundance of SGLT1 and GLUT2, respectively.In HS-adapted chickens, the serum concentration of aldosterone (means ± S.E.M.) was 35 ± 5 pg ml−1 (n = 6) and that of renin was 20 ± 2 ng ml−1 (n = 3). In LS-fed birds, these values were 166 ± 12 pg ml−1 (n = 6) and 122 ± 5 ng ml−1 (n = 3), respectively. Administration of captopril, the inhibitor of the angiotensin-converting enzyme (ACE), to LS-chickens lowered the aldosterone serum concentration without affecting the renin concentration. Captopril also prevented the reduction of apical and basolateral hexose transport in ileum and rectum characteristic of the intestinal response to LS adaptation.Administration of the aldosterone antagonist spironolactone to LS-adapted chickens did not affect the serum concentrations of aldosterone, but prevented the effects of LS intake on hexose transport in both apical and basolateral membranes. This suggests that the effects of aldosterone are mediated by cytosolic mineralcorticoid receptors.Administration of exogenous aldosterone to HS-fed birds induced hexose transport and binding properties typical of the LS-adapted animals. These findings support the view that aldosterone, besides its primary role in controlling intestinal Na+ absorption, can also modulate the expression of apical and basolateral glucose transporters in the chicken distal intestine.
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机译：class =“ enumerated” style =“ list-style-type：decimal”> <！-list-behavior =枚举前缀-word = mark-type = decimal max-label-size = 0-> 在鸡中，低Na + 饮食会显着降低大肠直肠部分的己糖转运。回肠中的转运显示较低，但显着减少，并且空肠中的转运不受影响。这些作用涉及顶端（SGLT1）和基底外侧（GLUT2）己糖转运蛋白。 肾素-血管紧张素-醛固酮轴（RAAS）在上皮对Na + 的反应中的作用研究了饲喂高NaCl（HS）和低NaCl（LS）日粮的鸡的摄入量。分别从刷边界（BBMV）和基底外侧（BLMV）膜中的囊泡中确定α-甲基-D-葡萄糖苷和D-葡萄糖的Vmax。 phlorizin与BBMV的结合以及cytochalasin B与BLMV的结合分别指示SGLT1和GLUT2的丰度。 在适应HS的鸡中，醛固酮的血清浓度（平均值±SEM）为35 ±5 pg ml -1 （n = 6），而肾素为20±2 ng ml -1 （n = 3）。在LS喂养的鸟类中，这些值分别为166±12 pg ml -1 （n = 6）和122±5 ng ml -1 （n = 3）。 。将卡托普利（血管紧张素转换酶（ACE）的抑制剂）给予LS鸡可降低醛固酮的血清浓度，而不影响肾素的浓度。卡托普利还可以防止回肠的根尖和基底外侧己糖运输减少以及肠对LS适应的肠特征。 向适应LS的鸡施用醛固酮拮抗剂螺内酯并不影响醛固酮的血清浓度，但阻止了LS摄入对顶膜和基底外侧膜中己糖转运的影响。这表明醛固酮的作用是由胞质盐皮质激素受体介导的。 将外源性醛固酮给予HS喂养的家禽，会产生适应LS的动物典型的己糖转运和结合特性。这些发现支持这样的观点，即醛固酮除了在控制肠道Na + 吸收中起主要作用外，还可以调节鸡远端肠中顶端和基底外侧葡萄糖转运蛋白的表达。
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