Uterine Growth Promoting Action of Relaxin

Abstract

Summary

Experiments were performed to determine response of uteri of immature albino rats to subcutaneous injections of varying dosages of relaxin. Saline and 0.0002, 0.001, 0.01, 0.1, 1, 5, and 10 mg relaxin were injected into female rats 28 and 33 days old by dividing the dose into thirds and administering each third on 3 consecutive days. Necropsies were performed on the fourth day at ages 31 and 36 days, respectively, and the uteri weighed, dried and reweighed. Wet uterine weights, i.e. mg % of body weight, increased along a sigmoid pattern from 45 for saline to 67 for 10 mg in younger group, and from 47 for saline to 70 for 10 mg in older group. Water concentration remained relatively constant, varying between 82 and 87% of wet weights, with no correlation as to amount of relaxin received. Nitrogen content showed a similar response, ranging between 12 and 14% for 36-day-old animals, and 12 and 16% for 31-day-old animals.