Relaxin, Insulin and Diabetes: An Intriguing Connection

摘要

Until recently, relaxin and insulin were grouped into the same hormone superfamily because of substantial biochemicalnhomologies. This notion has then changed with the understanding that insulin and relaxin are ligands for differentnreceptors and signal transduction systems, namely, tyrosine kinase and G-protein-coupled receptors respectively. As anmatter of fact, relaxin does not mimic the metabolic effects of insulin. The biological effects of insulin are much morenclearly delineated than those of relaxin, which is traditionally viewed as a reproductive hormone involved in the maternalnadjustments of pregnancy. In the last decade, evidence has been accumulating that relaxin has major effects on the heart,nblood vessels and the extracellular matrix within connective tissues. In particular, pertaining to the relationships betweennrelaxin and diabetes, relaxin was shown to promote arterial and microvascular dilation, thereby increasing organnperfusion, counteract ischemic injury, improve adverse cardiac and vascular remodeling, and promote extracellular matrixnturn-over, thereby exerting anti-fibrotic effects. Thus, relaxin could blunt or delay the vascular and organ complication ofndiabetes. Whether relaxin may also synergize with insulin to optimize blood glucose homeostasis remains an unconfirmednissue. However, there are clues in the literature which, if gathered, speak in favor of this perspective. Moreover,npreliminary data suggest that exogenous relaxin administration may improve insulin sensitivity in diabetic patients.nConsidering that human recombinant relaxin is under study as a novel, promising drug for the treatment of heart failure, anbroader knowledge of the possible beneficial effects of relaxin in diabetes and its complications can be of interest to thenscientific community.