Relaxin hormone

Relaxin is a peptide hormone that was initially defined in 1926 by Frederick Hisaw. Relaxin is a natural human peptide that affects multiple vascular control pathways.

A randomized, double-blind, placebo-controlled trial of relaxin for cervical ripening in post-delivery date pregnancies.
Ann N Y Acad Sci. 2009 Apr; Weiss G, Teichman S, Stewart D, Nader D, Wood S, Unemori E. Department of Obstetrics, Gynecology and Women's Health, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA.
Recombinant human relaxin was used to attempt cervical ripening in post-delivery date pregnancies. High doses of relaxin were safe but did not advance cervical ripening or induce labor.

Recombinant human relaxin in the treatment of systemic sclerosis with diffuse cutaneous involvement: a randomized, double-blind, placebo-controlled trial.
Arthritis Rheum. 2009 Apr; Khanna D, Clements PJ, Furst DE, Korn JH, Ellman M, Rothfield N, Wigley FM, Moreland LW, Silver R, Kim YH, Steen VD, Firestein GS, Kavanaugh AF, Weisman M, Mayes MD, Collier D, Csuka ME, Simms R, Merkel PA, Medsger TA Jr, Sanders ME, Maranian P, Seibold JR; Relaxin Investigators and the Scleroderma Clinical Trials Consortium. David Geffen School of Medicine, and School of Public Health, University of California, Los Angeles, USA.
A phase II randomized controlled trial of recombinant human relaxin suggested that a dosage of 25 microg/kg/day was safe and clinically effective in improving skin disease and reducing functional disability in scleroderma (systemic sclerosis; SSc). We undertook a large randomized, double-blind, placebo-controlled clinical trial to compare placebo with 10 microg/kg/day and 25 microg/kg/day recombinant human relaxin, given for 24 weeks in patients with stable, diffuse, moderate-to-severe SSc. Men and women ages 18-70 years with diffuse cutaneous SSc (dcSSc) were administered recombinant human relaxin (10 microg/kg/day or 25 microg/kg/day) or placebo for 24 weeks as a continuous subcutaneous infusion. There was a followup safety visit at week 28. Recombinant relaxin was not significantly better than placebo in improving the total skin score or pulmonary function or in reducing functional disability in patients with systemic sclerosis. In addition, relaxin was associated with serious renal adverse events, the majority of which occurred after stopping the infusion. If relaxin is used therapeutically for any conditions other than scleroderma, close monitoring of blood pressure and renal function must be performed.

Relaxin for the treatment of patients with acute heart failure (Pre-RELAX-AHF): a multicentre, randomised, placebo-controlled, parallel-group, dose-finding phase IIb study.
Lancet. 2009 Apr 25; Teerlink JR, Metra M, Felker GM, Ponikowski P, Voors AA, Weatherley BD, Marmor A, Katz A, Grzybowski J, Unemori E, Teichman SL, Cotter G.
Section of Cardiology, San Francisco Veterans Affairs Medical Center, University of California, San Francisco, CA, USA.
In a placebo-controlled, parallel-group, dose-ranging study, 234 patients with acute heart failure, dyspnoea, congestion on chest radiograph, and increased brain natriuretic peptide (BNP) or N-terminal prohormone of BNP, mild-to-moderate renal insufficiency, and systolic blood pressure greater than 125 mm Hg were recruited from 54 sites in eight countries and enrolled within 16 h of presentation. Patients were randomly assigned, in a double-blind manner via a telephone-based interactive voice response system, to standard care plus 48-h intravenous infusion of placebo (n=62) or relaxin 10 microg/kg (n=40), 30 microg/kg (n=43), 100 microg/kg (n=39), or 250 microg/kg (n=50) per day. When given to patients with acute heart failure and normal-to-increased blood pressure, relaxin was associated with favourable relief of dyspnoea and other clinical outcomes, with acceptable safety.

Association of serum relaxin with striae gravidarum in pregnant women.
Arch Gynecol Obstet. 2010 Jan 3. Lurie S, Matas Z, Fux A, Golan A, Sadan O. Department of Obstetrics and Gynecology, Edith Wolfson Medical Center, Holon, Israel, The cause of striae gravidarum is still unclear. The study objective was to test the hypothesis that relaxin is involved in the process of striae gravidarum appearance during pregnancy. A prospective observational study in 32 pregnant women. Participants were observed at 12th, 24th and 36th gestational week. During each session, striae scoring was assessed and blood for relaxin estimation was withdrawn. The striae assessment was done according to Davey score. Serum relaxin was estimated using Relaxin ELISA kit (Immunodiagnostic AG, Bensheim, Germany). Serum relaxin levels decreased as the pregnancy advanced but this decrease did not attain statistical significance. Pregnant women with striae gravidarum had lower serum relaxin levels compared to those without striae gravidarum at 36th gestational weeks. The severity of striae gravidarum during pregnancy did not correlate with serum relaxin levels. Lower serum relaxin levels could contribute to the occurrence of striae gravidarum during pregnancy through decreased elasticity of the connective tissue.

Inquiries
Can you give me your opinion on a product called Vitalxin which contains Porcine Relaxin 20 mcg, Trypsin Inhibitor 20 mcg, and Bovine Colostrum
    I am not familiar with Vitalaxin product. A search on Medline in March 2010 does not show any studies with this dietary supplement.