Effect of short-term infusion of recombinant human relaxin on blood pressure in the late-pregnant rhesus macaque (Macaca mulatta).

Abstract

To test a recombinant human relaxin preparation, developed for potential therapeutic application, for possible hypotensive actions in near-term pregnant rhesus monkeys. Groups of four females received 1-hour intravenous infusions of 0, 0.1, or 2.0 mg recombinant human relaxin/kg on gestation day 147 (term = 165 days). Maternal heart rate, electrocardiogram, and diastolic, systolic, and mean arterial pressure; and fetal heart rate were monitored before, during, and after the infusion. After spontaneous delivery, physical, neurobehavioral, and physiologic examinations were conducted on the newborn. No effects of recombinant human relaxin were detected by statistical analysis or examination of data records. Intravenous infusion of up to 2.0 mg recombinant human relaxin/kg in conscious pregnant rhesus monkeys had no effect on maternal cardiovascular indices or fetal heart rate.