The Physiological Role of Relaxin in the Pregnant Rat. II. The Influence of Relaxin on Uterine Contractile Activity

摘要: In control intact rats (group C), the frequency of intrauterine pressure cycles (IUPC) declines steadily during pregnancy from 80-130 cycles/3 h on day 10 (D10) to 20-30 D20. The decline in is due increasingly prolonged periods myometrial quiescence, which increase 30-90 min/3 D10 120-150 by During 24 preceding labor, IUPC remains at less than 15 cycles/h until 3 prepartum, when there an abrupt 30 cycles/h. Ovariectomized pregnant animals treated with progesterone (P) and estrogen (E; group OPE) exhibit significantly greater lower incidence quiescence D12 for remainder pregnancy. that received P, E, porcine relaxin (R: OPER) or P R only OPR) exhibited declining similar observed C animals. Group OPER duration those rats. OPR animals, however, were considerably diminished late a pattern activity labor postpartum results suggest important role second half parturition rat.