Cardiac effects of relaxin in rats

Lancet. 1992 May 2;339(8801):1076-8. doi: 10.1016/0140-6736(92)90665-p.


Relaxin is usually considered to be a hormone of pregnancy, but porcine relaxin has been shown to increase heart rate in rats. We investigated the cardiac effects of synthetic human gene-2 relaxin (hRlx-2) in vitro in isolated rat atria. Synthetic hRlx-2 produced concentration-dependent positive chronotropic effects in spontaneously beating right atria (EC50 [concentration required to produce 50% of the maximal response] = 0.09 [SE 0.03] nmol/l) and concentration-dependent positive inotropic effects in electrically driven left atria (EC50 = 0.31 [0.02] nmol/l). The potency of hRlx-2 is greater than that of endothelin, angiotensin II, and (-)-isoprenaline in isolated rat atria. Relaxin has powerful chronotropic and inotropic effects on the heart that are probably mediated through a direct action on relaxin receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / pharmacology
  • Animals
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Isoproterenol / pharmacology
  • Male
  • Myocardial Contraction / drug effects*
  • Rats
  • Rats, Inbred Strains
  • Relaxin / pharmacology*
  • Reserpine / pharmacology


  • Angiotensin II
  • Reserpine
  • Relaxin
  • Isoproterenol