HORMONAL-REGULATION OF GLUCONEOGENESIS IN CULTURED PROXIMAL TUBULAR CELLS - ROLE OF CYTOSOLIC CALCIUM
HORMONAL-REGULATION OF GLUCONEOGENESIS IN CULTURED PROXIMAL TUBULAR CELLS - ROLE OF CYTOSOLIC CALCIUM
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DOI：
10.1152/ajprenal.1987.253.5.f802
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发表时间：
1987-11-01
影响因子：
--
通讯作者：
KARL, IE
中科院分区：
文献类型：
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作者：
GOLIGORSKY, MS;OSBORNE, D;KARL, IE
本文研究了犬肾近曲小管细胞原代培养的糖异生能力。与生长在20 mM葡萄糖培养基中的细胞相反，生长在5 mM葡萄糖培养基或无葡萄糖培养基中的细胞表现出琥珀酸盐刺激的葡萄糖产生。在最后一次培养基更换后72小时，在5 mM葡萄糖培养基中生长的汇合细胞从主要的糖酵解代谢转变为氧化代谢。此时，葡萄糖产生表现出pH、3-巯基吡啶甲酸盐和胰岛素敏感性。甲状旁腺激素、血管紧张素II和苯丙氨酸以非加性方式刺激葡萄糖生成。使用显微荧光光谱技术的单细胞cytoprotein Ca 2+测量结果显示，所有三种激素引起近端肾小管细胞中的Ca 2+瞬变。离子霉素刺激近端肾小管细胞产生葡萄糖，这表明Ca 2+瞬变可以代表葡萄糖产生的足够刺激。当通过用膜渗透性Ca 2+螯合剂Maptam进行预处理来减少Ca 2+诱导的Ca 2+瞬变时，葡萄糖产生的激素刺激被废除，这表明Ca 2+瞬变不仅是足够的，而且是这些激素刺激葡萄糖产生的必要事件。
Gluconeogenic competence of primary cultures of canine rneal proximal tubular cells has been examined. Cells grown in 5 mM glucose media or in glucose-free media exhibited pyruvate-stimulated glucose production, as opposed to cells grown in 20 mM glucose media. By 72 h after the last media change, confluent cells grown in 5 mM glucose medium turn from a predominantly glycolytic to an oxidative type of metabolism. By this time, glucose production exhibited pH, 3-mercaptopicolinate, and insulin sensitivity. Parathyroid hormone, angiotensin II, and phenylephrine stimulated glucose production in a nonadditive fashion. Single-cell cystolic Ca2+ measurements using microspectrofluorometric techniques revealed that all three hormones elicited Ca2+ transients in proximal tubular cells. Ionomycin stimulated glucose production by proximal tubular cells, suggesting that Ca2+ transients could represent a sufficient stimulus for glucose production. When hormone-induced Ca2+ transients were curtailed by a pretreatment with the membrane-permeant Ca2+ chelator, Maptam, hormonal stimulation of glucose production was abolished, suggesting that Ca2+ transients represent not only a sufficient, but a necessary event in the stimulation of glucose production by these hormones.