Charlton J A, Baylis P H
Department of Medicine, New Medical School, Newcastle upon Tyne.
J Endocrinol. 1989 Jun;121(3):435-9. doi: 10.1677/joe.0.1210435.
Arginine vasopressin (AVP) stimulates Na+ K+ ATPase and ornithine decarboxylase (ODC) activity in the rat medullary thick ascending limb. The effect of difluoromethyl ornithine (DFMO), a specific inhibitor of ODC activity, on AVP-stimulated Na+ K+ ATPase activity was evaluated using a cytochemical bioassay. Peaks in Na+ K+ ATPase activity in cultured rat renal segments which occurred after tissue had been exposed to 1 fmol AVP/l were completely inhibited by the addition of 20 mmol DFMO/l to the culture medium containing AVP. The addition of 20 mmol DFMO/l to the culture medium containing AVP in the concentration range 0.001-10 fmol/l inhibited completely the stimulation of Na+ K+ ATPase activity by AVP. The response of Na+ K+ ATPase to increasing doses of ATP (10-40 g polypeptide/l) was not influenced by the addition of 20 mmol DFMO/l to the culture medium containing AVP, suggesting that the prevention of AVP-stimulated Na+ K+ ATPase activity by DFMO was not due to a direct effect on the enzyme.
精氨酸加压素（AVP）可刺激大鼠髓质厚升支中的钠钾ATP酶和鸟氨酸脱羧酶（ODC）活性。使用细胞化学生物测定法评估了ODC活性的特异性抑制剂二氟甲基鸟氨酸（DFMO）对AVP刺激的钠钾ATP酶活性的影响。在组织暴露于1 fmol AVP/升后，培养的大鼠肾段中出现的钠钾ATP酶活性峰值，在向含有AVP的培养基中添加20 mmol DFMO/升后被完全抑制。在含有浓度范围为0.001 - 10 fmol/升AVP的培养基中添加20 mmol DFMO/升，可完全抑制AVP对钠钾ATP酶活性的刺激。向含有AVP的培养基中添加20 mmol DFMO/升，对钠钾ATP酶对增加剂量的ATP（10 - 40 μg多肽/升）的反应没有影响，这表明DFMO对AVP刺激的钠钾ATP酶活性的抑制作用不是由于对该酶的直接作用。
