Regulatory influence of relaxin on human cervical and uterine connective tissue.

Cervical tissue was obtained from women undergoing legal abortion in the 7th-15th week of gestation and tissue from the lower uterine segment was excised at elective Casearean section in the 38th-40th week. The specimens were incubated with [3H]proline in the presence of relaxin or prostaglandin E2 (PGE2). Relaxin had a concentration related inhibitory effect on the radiolabelling in the 7th-9th week but failed to influence the amino acid uptake in the 10th-15th week of pregnancy. PGE2 had the inverse effect, i.e. no influence in the former group but reduced incorporation of proline in the latter group of patients. Incubation of tissue from the lower uterine segment showed a similar response as that of the early pregnant cervix. It is concluded that relaxin has a significant influence on [3H]proline incorporation by cervical and uterine tissue under in vitro experimental conditions.