Biochemical studies suggest that G-protein-coupled receptors (GPCRs) achieve exquisite signalling specificity by forming selective complexes, termed signalosomes. Here, using cAMP biosensors in single cells, we uncover a pre-assembled, constitutively active GPCR signalosome, that couples the relaxin receptor, relaxin family peptide receptor 1 (RXFP1), to cAMP following receptor stimulation with...

The mechanisms involved in cardiovasular changes during human pregnancy and the complicated aetiology of gestational hypertension are unclear. Reproductive hormones have known effects on the cardiovascular system in the non-pregnant state and in animal systems, but their effects in human pregnancy are uncertain. In this study of pregnant women, the effects of serum concentrations of relaxin, pr...

The changes in knee laxity and relaxin receptor expression at different phases of rodent estrous cycle are not known. Here, changes in the parameter were investigated in rats at different phases of the estrous cycle. Estrous cycle phases of intact female rats were determined by cytological examination of the vaginal smear. Following phase identification, blood was collected for serum hormone an...

The relaxin family peptides play a variety of biological functions by activating four G protein-coupled receptors, RXFP1-4. Among them, insulin-like peptide 5 (INSL5) and relaxin-3 share the highest sequence homology, but they have distinct receptor preference: INSL5 can activate RXFP4 only, while relaxin-3 can activate RXFP3, RXFP4, and RXFP1. Previous studies suggest that the A-chain is respo...

The nucleus incertus (NI), a brainstem nucleus found in the pontine periventricular grey, is the primary source of the neuropeptide relaxin-3 in the mammalian brain. The NI neurons have also been previously reported to express several receptors and neurotransmitters, including corticotropin releasing hormone receptor 1 (CRF₁) and gamma-aminobutyric acid (GABA). The NI projects widely to putativ...

In their recent publication, Damp et al. (1), reported that early postpartum levels of relaxin-2 are associated with better short-term left ventricular function in women with peripartum cardiomyopathy (PPCM). This is of potential interest given our incomplete understanding of the pathophysiology of PPCM. However, it is important to note that the investigators have not taken the women’s weight o...

In a paper published by the FASEB Journal in 1999, Danielle Georges and Christian Schwabe described gene sequences from the tunicate Ciona intestinalis that were indistinguishable from porcine relaxin (1). Newer data contradict that finding: recently published analyses of the C. intestinalis genome do not confirm the presence of relaxin sequences (2). What might seem like a narrow issue of scie...

INSL5 (insulin-like peptide 5) is a two-chain peptide hormone related to insulin and relaxin. It was recently discovered through searches of expressed sequence tag databases and, although the full biological significance of INSL5 is still being elucidated, high expression in peripheral tissues such as the colon, as well as in the brain and hypothalamus, suggests roles in gut contractility and n...

Relaxin, when administered to mice pretreated with estrogen, induces a transformation of the joint cartilage into ligamentous tissue. This transformation , which results in an increased distance between the pubic bones that border the joint, is similar to that occurring during normal pregnancy."'2 The increase in interpubic distance following relaxin treatment has been the chief criterion used ...

BACKGROUND Women are recommended to perform regular exercise during pregnancy but the impact of physical fitness on duration of gestation and miscarriage is inconsistent. In addition, a dose-response relation between the amount of weekly exercise and increased risk of miscarriage in early pregnancy has been observed. Previous studies have mostly used an epidemiologic method. Larger studies usin...