Kano H, Kohno M, Yasunari K, Yokokawa K, Horio T, Ikeda M, Minami M, Hanehira T, Takeda T, Yoshikawa J
First Department of Internal Medicine, Osaka City University Medical School, Japan.
J Hypertens. 1996 Feb;14(2):209-13. doi: 10.1097/00004872-199602000-00009.
The present study was designed to examine whether adrenomedullin affects fetal calf serum (FCS)-stimulated proliferation in cultured rat vascular smooth muscle cells (VSMCs).
Rat VSMCs were grown from explants of Sprague-Dawley rat aorta and were grown using the standard cell culture method. After incubation for 24 h with various concentrations of adrenomedullin in the presence of 5% FCS, trichloroacetic acid-insoluble tritiated thymidine was measured in a liquid scintillation counter. After incubation for 48 h, cell counts were performed. Cyclic adenosine 3',5'-monophosphate (AMP) levels were determined by radioimmunoassay.
Rat adrenomedullin exhibited concentration-dependent inhibition of the FCS-stimulated increase in thymidine incorporation between 10(-7) and 10(-9) mol/l and of cell number at 10(-7) mol/l. However, the calcitonin generelated peptide (CGRP) receptor antagonist human CGRP(8-37) abolished these antiproliferative effects of rat adrenomedullin. Inhibition by adrenomedullin of FCS-stimulated cellular proliferation was paralleled by an increase in the cellular level of cyclic AMP. 8-Bromocyclic AMP, a cyclic AMP analogue, and forskolin, an activator of adenylate cyclase, inhibited the FCS-stimulated increase in thymidine incorporation and cell number.
These results suggest that adrenomedullin inhibits FCS-stimulated proliferation in cultured rat VSMCs, probably through a cyclic AMP-dependent process. Taken together with the finding that adrenomedullin is synthesized in and secreted from vascular endothelial cells, adrenomedullin may play a role as an antiproliferative factor for VSMCs in a paracrine fashion.
本研究旨在检测肾上腺髓质素是否影响胎牛血清（FCS）刺激的培养大鼠血管平滑肌细胞（VSMCs）增殖。
从Sprague-Dawley大鼠主动脉外植体培养大鼠VSMCs，并采用标准细胞培养方法。在5% FCS存在下，用不同浓度的肾上腺髓质素孵育24小时后，在液体闪烁计数器中测量三氯乙酸不溶性氚标记胸腺嘧啶核苷。孵育48小时后，进行细胞计数。通过放射免疫测定法测定环磷腺苷（AMP）水平。
大鼠肾上腺髓质素在10⁻⁷至10⁻⁹ mol/l之间对FCS刺激的胸腺嘧啶核苷掺入增加呈浓度依赖性抑制，在10⁻⁷ mol/l时对细胞数量也有抑制作用。然而，降钙素基因相关肽（CGRP）受体拮抗剂人CGRP（8-37）消除了大鼠肾上腺髓质素的这些抗增殖作用。肾上腺髓质素对FCS刺激的细胞增殖的抑制作用与细胞内环磷腺苷水平的增加平行。环磷腺苷类似物8-溴环磷腺苷和腺苷酸环化酶激活剂福斯可林抑制了FCS刺激的胸腺嘧啶核苷掺入增加和细胞数量增加。
这些结果表明，肾上腺髓质素可能通过环磷腺苷依赖性过程抑制培养大鼠VSMCs中FCS刺激的增殖。结合肾上腺髓质素在血管内皮细胞中合成和分泌的发现，肾上腺髓质素可能以旁分泌方式作为VSMCs的抗增殖因子发挥作用。
