Relaxin

Relaxin molecule

Relaxin is a peptide hormone.[1]

Function

In humans

Relaxin is produced in females. It rises to a peak about 14 days after ovulation, and then declines if the egg is not fertilised. During the first three months of pregnancy, levels rise and more relaxin is produced. Relaxin adjusts blood supply during pregnancy. It also relaxes pelvic ligaments.[2] It softens the pubic symphysis (the ligaments joining the bottom of the pelvis).

In males, relaxin also has a function: it enhances motility of sperm in semen.[3]

In other animals

In animals, relaxin widens the pubic bone and facilitates labor. It also softens the cervix (cervical ripening), and relaxes the uterine musculature. Thus, for a long time, relaxin was looked at as a pregnancy hormone. However, its significance may reach much further. Relaxin affects collagen metabolism, inhibiting collagen synthesis and enhancing its breakdown.[4]

References

  1. Bani D. Relaxin: a pleiotropic hormone.. General Pharmacology 28 (1) (1997). p. 13–22. doi:10.1016/s0306-3623(96)00171-1.
  2. Conrad K.P.. Maternal vasodilation in pregnancy: the emerging role of relaxin. Am. J. Physiol. Regul. Integr. Comp. Physiol. 301 (2) (2011). p. R267–75. doi:10.1152/ajpregu.00156.2011.
  3. Weiss G. Relaxin in the male. Biol. Reprod. 40 (2) (1989). p. 197–200. doi:10.1095/biolreprod40.2.197. Retrieved 2017-06-24.
  4. Tang, Mimi L. K.. Endogenous relaxin regulates collagen deposition in an animal model of allergic airway disease. Endocrinology 147 (2) (2006). p. 754–61. doi:10.1210/en.2005-1006.