SUBTERRANEAN MOLE-RATS NATURALLY HAVE AN IMPOVERISHED CALCIOL STATUS, YET SYNTHESIZE CALCIOL METABOLITES AND CALBINDINS
SUBTERRANEAN MOLE-RATS NATURALLY HAVE AN IMPOVERISHED CALCIOL STATUS, YET SYNTHESIZE CALCIOL METABOLITES AND CALBINDINS
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DOI：
10.1530/eje.0.1300402
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发表时间：
1994-04-01
影响因子：
5.8
通讯作者：
PETTIFOR, JM
中科院分区：
文献类型：
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作者：
BUFFENSTEIN, R;JARVIS, JUM;PETTIFOR, JM
鼹鼠(Bathyergidae科)没有明显的钙醇来源。它们生活在缺乏阳光的环境中，以草食为食。研究了6种Bathyergids的钙质状况、代谢和表达情况。与其他啮齿动物相比，所有物种的血清骨化二醇水平均为<；5mU/L，骨化三醇水平较低(18.0/-11.0(SD)ng/L，N=57)。在给动物注射氚标记的钙醇后的72小时内，大多数标记的前激素已被代谢成更多的极性代谢物。氚标记骨化三醇(19.3+/-2.9%)是(24R)-羟基骨化二醇(6.2+/-10%)的三倍。天然没有可检测到的循环钙二醇浓度，产生的骨化三醇是(24R)-羟基钙二醇的三倍，这表明钙醇自然供应不足。十二指肠内没有钙依赖的钙结合蛋白。Calbindin-D-28k表达于小脑浦肯野细胞、部分集合管以及肾近曲小管和远曲小管。Calbindin-D-9k也存在，但仅定位于五个南部非洲物种的肾小球旁细胞。这些数据证实了Bathyergid鼹鼠天生就有一种贫乏的钙质状态。尽管在肾组织中存在钙结合蛋白，但这种激素在钙结合蛋白合成和其他正常的摩尔大鼠生理中的功能重要性尚不清楚。
Mole-rats (Family Bathyergidae) have no obvious source of calciol. They live in an environment devoid of sunlight and consume a herbivorous diet. Calciol status, metabolism and expression were examined in six species of Bathyergids. Serum levels of calcidiol In all species were < 5 mu g/l and those of calcitriol were low (18.0 +/- 11.0 (SD) ng/l, N = 57) when compared to other rodents. Within 72 h of injecting animals with tritium-labelled calciol, most of the labelled prohormone had been metabolized to more polar metabolites. Three times more tritium-labelled calcitriol(l9.3 +/- 2.9%) was present than (24R)-hydroxycalcidiol (6.2 +/- 10%). The natural absence of detectable circulating concentrations of calcidiol and the threefold greater amount of calcitriol to (24R)-hydroxycalcidiol produced indicate that calciol naturally is in short supply. Calciol-dependent calbindins were absent in the duodenum. Calbindin-D-28k was present in the Purkinje cells of the cerebellum and in some collecting ducts and proximal and distal convoluted tubules of the kidney. Calbindin-D-9k also was present but was localized uniquely in the juxtaglomerular cells of the five southern African species. These data confirm that Bathyergid mole-rats naturally have an impoverished calciol status. Despite the presence of calbindins in renal tissues, the functional importance of this hormone in calbindin synthesis and other normal mole-rat physiology is not known.