Cardiac effects of relaxin in rats

H. Kakouris, L. W. Eddie, R. J. Summers

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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. Lancet 1992; 339: 1076-78.

Original languageEnglish
Pages (from-to)1076-1078
Number of pages3
JournalThe Lancet
Issue number8801
Publication statusPublished - 2 May 1992

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