RXFP1, the relaxin receptor: Lost and found in translation.

Relaxin, historically recognized as a pregnancy hormone, is today characterized as a circulating protein possessing several cardiovascular modulating and anti-fibrotic properties of high clinical interest. Although it has long been recognized that there exists remarkable species diversity regarding the tissue sources and physiological effects of relaxin, there is a considerable gap in our translational understanding of its signal transducing receptor, relaxin family peptide receptor 1 (RXFP1). Here, we review the topic and highlight the striking contrast in RXFP1 tissue expression from rodents to humans, and describe how a renewed focus on RXFP1 target pharmacology is critical to delivering future clinical success in relation to this physiologically important signaling receptor.