title: Effect of relaxin on human sperm functions.
abstract: Relaxin is a circulating hormone with functions in pregnancy, parturition,  and other aspects of female reproduction. It is also secreted from the  prostate gland into the seminal fluid; however, the role of relaxin in male  reproduction is debated. Studies conducted in the past have suggested possible  actions on human spermatozoa, but the data were contrasting. Here, we show  that the relaxin receptor RXFP1 (Relaxin Family Peptide Receptor 1) is  expressed in human spermatozoa, and it mainly localizes in the astrodome. In  vitro studies on human sperm demonstrated that this hormone attenuates the  natural decline in sperm motility and maintains higher mitochondrial activity  and lower apoptosis level. Furthermore, relaxin induced an increase in sperm  hyperactivation, intracellular calcium and cAMP, and acrosome reaction. These  effects were abolished by the use of the specific anti-RXFP1 antibody. Relaxin  concentrations were low in the blood  (x ± SD, 0.16 ± 0.03 nM)  and very high in the seminal plasma (x  ± SD, 10.3 ± 4.0 nM), confirming its secretion mainly by the  prostate. Taken together, these data demonstrate that relaxin influences  positively many sperm functions linked to fertilizing ability, and it  preserves sperm functionality, with possible practical value in assisted  reproduction techniques.
authors: University of Padova, Department of Histology, Microbiology and Medical Biotechnologies, Section of Clinical Pathology and Center for Male Gamete Cryopreservation, Padova, Italy.
authors: Alberto
authors: A
authors: Ferlin
authors: Massimo
authors: M
authors: Menegazzo
authors: Lisa
authors: L
authors: Gianesello
authors: Riccardo
authors: R
authors: Selice
authors: Carlo
authors: C
authors: Foresta
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology; D017209:Apoptosis / Q000502:physiology; D053627:Asthenozoospermia / Q000503:physiopathology; D002118:Calcium / Q000032:analysis; D000242:Cyclic AMP / Q000032:analysis; D005306:Fertilization / Q000502:physiology; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D011467:Prostate / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000032:analysis / Q000378:metabolism*; D018000:Receptors, Peptide / Q000032:analysis / Q000378:metabolism*; D012065:Relaxin / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D055101:Semen Analysis; D013075:Sperm Capacitation / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
chemical_list: C417543:RXFP1 protein, human; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D012065:Relaxin; D000242:Cyclic AMP; D002118:Calcium