Unwin R, Capasso G, Giebisch G
Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520-8026.
Am J Physiol. 1995 Feb;268(2 Pt 2):F234-9. doi: 10.1152/ajprenal.1995.268.2.F234.
The role of adrenal steroids in the regulation of bicarbonate absorption in the loop of Henle was studied by in vivo microperfusion. Bicarbonate transport (JHCO3) was measured by microcalorimetry and fluid reabsorption by [14C]inulin, 7-10 days after surgery, in 1) sham-operated control rats, 2) adrenalectomized (Adx) rats, 3) Adx rats receiving dexamethasone (1.2 micrograms.100 g body wt-1.24 h-1) and a low dose of aldosterone (0.5 micrograms.100 g body wt-1.24 h-1), 4) Adx rats receiving dexamethasone, 5) Adx rats receiving a low dose of aldosterone, and 6) Adx rats receiving a high dose of aldosterone (1.0 micrograms.100 g body wt-1.24 h-1). JHCO3 along the loop of Henle was decreased by 40% in Adx rats. JHCO3 was increased by dexamethasone alone and by dexamethasone plus a low dose of aldosterone to rates observed in fully supplemented Adx rats. Aldosterone given alone at a low physiological dose had no effect, but, when administered at a high dose, returned JHCO3 to normal.
通过体内微灌注研究了肾上腺类固醇在调节亨利袢碳酸氢盐重吸收中的作用。在手术后7 - 10天，通过微量量热法测量碳酸氢盐转运（JHCO3），并通过[14C]菊粉测量液体重吸收，实验对象包括：1）假手术对照大鼠；2）肾上腺切除（Adx）大鼠；3）接受地塞米松（1.2微克·100克体重-1·24小时-1）和低剂量醛固酮（0.5微克·100克体重-1·24小时-1）的Adx大鼠；4）接受地塞米松的Adx大鼠；5）接受低剂量醛固酮的Adx大鼠；6）接受高剂量醛固酮（1.0微克·100克体重-1·24小时-1）的Adx大鼠。Adx大鼠亨利袢的JHCO3降低了40%。单独使用地塞米松以及地塞米松加低剂量醛固酮可使JHCO3增加至完全补充的Adx大鼠中观察到的水平。低生理剂量单独给予醛固酮没有效果，但高剂量给药时可使JHCO3恢复正常。
