Parathyroid hormone regulation of cytosolic Ca2+ in rat proximal tubules.
Parathyroid hormone regulation of cytosolic Ca2+ in rat proximal tubules.
复制标题
甲状旁腺激素对大鼠近曲小管胞浆 Ca2 的调节。
DOI：
10.1152/ajprenal.1990.258.3.f545
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
S. Harrison
中科院分区：
文献类型：
--
作者：
C. Filburn;S. Harrison
使用荧光指示剂 quin-2，在纯化的大鼠肾近曲小管的悬浮液中研究了甲状旁腺激素 (PTH) 对胞质 Ca2+ 的影响。大鼠 PTH-(1-34) 在 20 秒内使表观胞质 Ca2+ 短暂增加 40%，随后迅速恢复至基础水平。对于大鼠PTH-(1-34)，上升速率和峰值表观Ca2+ 的半最大剂量均为3 X 10(-8) M。与 PTH 不同，毛喉素和二丁酰腺苷 3',5'-环单磷酸没有立竿见影的效果。牛 PTH-(3-34) 以浓度依赖性方式阻断 PTH 的作用。将中等Ca2+急剧减少至低于10(-6) M对PTH-或血管紧张素II (ANG II)诱导的瞬变没有影响，但阻止任何持续的增加。在名义上不含 Ca2(+) 的培养基中洗涤小管，然后用乙二醇-双（β-氨基乙基醚）-N,N,N',N'-四乙酸洗涤小管，使两种瞬变均减少 50%。 2 X 10(-7) 的 PTH 引起[3H]肌醇磷酸盐积累的小幅增加 (6-9%)，与 10(-7) M 的去甲肾上腺素产生的积累相当。在 10(-7) M 时，去甲肾上腺素产生的 Ca2+ 和肌醇磷酸盐的增加与 PTH 相似；在 10(-5) M 时，肌醇磷酸发生了更大的增加。在施用 PTH 之前暴露于高水平的去甲肾上腺素或 ANG II 可防止 PTH 或其他激动剂的任何后续刺激。次最大剂量的去甲肾上腺素仅轻微削弱 PTH 或 ANG II 的作用。（摘要截断为 250 字）
The effect of parathyroid hormone (PTH) on cytosolic Ca2+ was studied on suspensions of purified rat renal proximal tubules using the fluorescent indicator quin-2. Rat PTH-(1-34) produced a transient 40% increase in apparent cytosolic Ca2+ at 20 s, followed by a rapid return toward the basal level. The half-maximal dose for both the rate of rise and peak apparent Ca2+ was 3 X 10(-8) M for rat PTH-(1-34). Unlike PTH, forskolin and dibutyryl adenosine 3',5'-cyclic monophosphate had no immediate effect. Bovine PTH-(3-34) blocked the effect of PTH in a concentration-dependent manner. Acute reduction of medium Ca2+ to less than 10(-6) M had no effect on either PTH- or angiotensin II (ANG II)-induced transients, but prevented any sustained increases. Washing tubules in nominally Ca2(+)-free medium followed by ethylene glycol-bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid reduced both transients by 50%. PTH at 2 X 10(-7) caused small (6-9%) increases in accumulation of [3H]inositol phosphates comparable with that produced by norepinephrine at 10(-7) M. At 10(-7) M, norepinephrine produced increases in Ca2+ and inositol phosphates similar to PTH; at 10(-5) M much larger increases in inositol phosphates occurred. Exposure to high levels of either norepinephrine or ANG II before PTH administration prevented any subsequent stimulation by PTH or other agonists. A submaximal dose of norepinephrine only slightly blunted the effect of PTH or ANG II.(ABSTRACT TRUNCATED AT 250 WORDS)