Relaxin is a polypeptide hormone released by the corpus luteum (ovary), uterus, placenta and mammary gland. It plays an important role in pregnancy and childbirth, but there's still much mystery around the function of this multi-tasking hormone. Some of what we do know is that relaxin prevents uterine contractions early in pregnancy to avoid premature childbirth. During childbirth, it helps the cervix dilate and the vagina to soften and widen. In blood circulation, levels of relaxin rise after ovulation and lower again if pregnancy does not occur.  

Relaxin has also been discovered in men, although its function is even more unclear in men. Secreted by the prostate, it is found in semen. It is thought to assist the movement of sperm cells in the semen.

Recent findings show that relaxin also decreases tissue fibrosis in the heart, lungs, kidney and liver. It supports the growth of new blood vessels, helps heal wounds and is anti-inflammatory. Even though researchers are still figuring out what exactly it does, relaxin seems to be a pivotal hormone in various systems of the body, aside from just reproductive. Cool!

Human Hormones - List of All HormonesHumans make and circulate over 50 hormones, thanks to your  amazing endocrine network of glands. Hormones travel through the blood to help different organs talk to each other. The pea-sized pituitary gland, located in the brain, controls the release of seven different hormones that regulate sex drive, hunger and growth. Credit to the Word Cloud Generator for generating this graphic.