Central hemodynamic effects of recombinant human relaxin in the isolated, perfused rat heart model.
OBJECTIVE
To determine the cardiac effects of relaxin in the isolated, perfused rat heart model, and to see if pregnancy modifies the hormone's actions.


METHODS
Hearts were excised from 18 female Sprague-Dawley rats (ten pregnant, eight nonpregnant) and attached to a Langendorff apparatus. Left ventricular systolic pressure, heart rate, and contractility were measured. Hearts were exposed serially to 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 ng/mL concentrations of recombinant human relaxin.


RESULTS
Hearts from pregnant rats had lower heart rates than those from nonpregnant animals. Relaxin increased heart rate, left ventricular systolic pressure, and contractility in a dose-dependent fashion. Pregnancy did not modify this response.


CONCLUSIONS
Recombinant human relaxin is a potent inotropic and chronotropic agent. The effects coupled with the physiologic increase of relaxin during human pregnancy indicate that relaxin may be involved in the cardiovascular changes of pregnancy.
Coulson
C C
CC
Department of Obstetrics and Gynecology, Penn State University, College of Medicine, Hershey, Pennsylvania, USA.
Thorp
J M
JM
Mayer
D C
DC
Cefalo
R C
RC
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects; D011247:Pregnancy / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D012065:Relaxin / Q000494:pharmacology* / Q000502:physiology
D011994:Recombinant Proteins; D012065:Relaxin