Xue H, McCarron D A, Bukoski R D
Department of Medicine, Oregon Health Sciences University, Portland 97201.
Life Sci. 1991;49(9):651-9. doi: 10.1016/0024-3205(91)90111-n.
The effect of 1,25 (OH)2 vitamin D3 on basal 45Ca uptake was examined in vascular smooth muscle cells cultured from mesenteric arteries of spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) normotensive rats. Basal uptake of 45Ca was significantly greater in myocytes of WKY than SHR at 5, 10, 30 and 60 min incubation with the isotope. Incubation with 1 ng/ml 1,25 (OH)2 vitamin D3 for 48 hr increased basal 45Ca uptake between 1-10 min in SHR and between 5-10 min in WKY. The dose-response relationship indicated that cells from both strains are equally sensitive to the calciotropic effects of 1,25 (OH)2 vitamin D3 with half-maximal stimulation occurring at approximately 0.3-0.4 ng/ml. In cells of both strains maximal stimulation of 45Ca uptake was achieved only after a 12-24 hr period of incubation with hormone and pretreatment with cycloheximide inhibited 1,25 (OH)2 vitamin D3-enhanced 45Ca uptake. Although 45Ca binding by extracellular matrix material was significantly greater in WKY than SHR, 1,25 (OH)2 vitamin D3 had no effect on the amount of matrix 45Ca binding in either strain. These results suggest that 1,25 (OH)2 vitamin D3 induces an increase in intracellular protein synthesis that results in enhanced 45Ca uptake. The similar responses of the two strains indicate that hypertensive smooth muscle is not more sensitive to 1,25 (OH)2 vitamin D3 and the Ca2+ response is a general property of vascular muscle.
在源自自发性高血压大鼠（SHR）和Wistar Kyoto正常血压大鼠（WKY）肠系膜动脉培养的血管平滑肌细胞中，检测了1,25（OH）₂维生素D₃对基础⁴⁵Ca摄取的影响。在与该同位素孵育5、10、30和60分钟时，WKY肌细胞中⁴⁵Ca的基础摄取显著高于SHR。用1 ng/ml 1,25（OH）₂维生素D₃孵育48小时，可使SHR在1 - 10分钟内以及WKY在5 - 10分钟内基础⁴⁵Ca摄取增加。剂量反应关系表明，两种品系的细胞对1,25（OH）₂维生素D₃的钙调节作用同样敏感，半最大刺激发生在约0.3 - 0.4 ng/ml。在两种品系的细胞中，仅在与激素孵育12 - 24小时后，⁴⁵Ca摄取才达到最大刺激，用环己酰亚胺预处理可抑制1,25（OH）₂维生素D₃增强的⁴⁵Ca摄取。尽管WKY细胞外基质材料结合的⁴⁵Ca显著多于SHR，但1,25（OH）₂维生素D₃对两种品系中基质⁴⁵Ca结合量均无影响。这些结果表明，1,25（OH）₂维生素D₃诱导细胞内蛋白质合成增加，从而导致⁴⁵Ca摄取增强。两种品系的相似反应表明，高血压平滑肌对1,25（OH）₂维生素D₃并非更敏感，Ca²⁺反应是血管平滑肌的普遍特性。
