Samuel Chrishan S, Parry Laura J, Summers Roger J
Howard Florey Institute of Experimental Physiology & Medicine, University of Melbourne, Victoria 3010, Australia.
Curr Opin Pharmacol. 2003 Apr;3(2):152-8. doi: 10.1016/s1471-4892(03)00011-0.
The omnipresent 6kDa polypeptide relaxin (RLX) is emerging as a multi-functional endocrine and paracrine factor, with a broad range of target tissues that includes the cardiovascular system. Humans and other higher primates have three RLX genes, designated H1, H2 and H3, of which H2 RLX is the major stored and circulating form. Rodents have only two RLX genes: relaxin-1 (equivalent to H2 RLX) and relaxin-3 (equivalent to H3 RLX). The recent cloning of the human RLX receptor (LGR7), a member of the leucine-rich repeat family of G-protein-coupled orphan receptors, and detection of LGR7 gene transcripts in the heart confirm this organ as a target for RLX (H2). However, evidence for production of the ligand within the cardiovascular system is limited, and few studies have clearly identified the physiological effects of RLX on cardiac function. To add to the controversy, serum concentrations and expression of RLX in the heart are elevated in chronic heart failure patients and animal models of cardiomyopathy, implying that RLX may only be a marker for pathological cardiovascular conditions, rather than normal physiology.
无处不在的6 kDa多肽松弛素（RLX）正逐渐成为一种多功能内分泌和旁分泌因子，其靶组织广泛，包括心血管系统。人类和其他高等灵长类动物有三个RLX基因，分别命名为H1、H2和H3，其中H2 RLX是主要的储存和循环形式。啮齿动物只有两个RLX基因：松弛素-1（相当于H2 RLX）和松弛素-3（相当于H3 RLX）。人类RLX受体（LGR7）的克隆，它是富含亮氨酸重复序列的G蛋白偶联孤儿受体家族的成员，以及在心脏中检测到LGR7基因转录本，证实心脏是RLX（H2）的靶器官。然而，心血管系统内配体产生的证据有限，很少有研究明确确定RLX对心脏功能的生理作用。更具争议的是，慢性心力衰竭患者和心肌病动物模型中，心脏中RLX的血清浓度和表达升高，这意味着RLX可能只是病理性心血管疾病的标志物，而非正常生理状态的标志物。
