EFFECT OF SHORT-TERM INFUSION OF RECOMBINANT HUMAN RELAXIN ON BLOOD-PRESSURE IN THE LATE-PREGNANT RHESUS MACAQUE (MACACA-MULATTA)

Objective: To test a recombinant human relaxin preparation, developed for potential therapeutic application, for possible hypotensive action s in near-term pregnant rhesus monkeys. Methods: Groups of four female s received 1-hour intravenous infusions of: 0, 0.1, or 2.0 mg recombin ant human relaxin/kg on gestation day 147 (term = 165 days). Maternal heart rate, electrocardiogram, and diastolic, systolic, and mean arter ial pressure; and fetal heart rate were monitored before, during, and after the infusion. After spontaneous delivery, physical, neurobehavio ral, and physiologic examinations were conducted on the newborn. Resul ts: No effects of recombinant human relaxin were detected by statistic al analysis or examination of data records. Conclusion: Intravenous in fusion of up to 2.0 mg recombinant human relaxin/kg in conscious pregn ant rhesus monkeys had no effect on maternal cardiovascular indices or fetal heart rate. (Obstet Gynecol 1994;83:85-8)