Separation of relaxin activities in extracts of ovaries of pregnant sows by polyacrylamide gel electrophoresis.

Polyacrylamide gel electrophoresis has been employed to separate three fractions that have relaxin activity from crude extracts of ovaries of pregnant sows. Bioassays indicated that all fractions had the ability to inhibit spontaneous uterine contractions in vitro and to induce formation of interpubic ligaments in oestrogen-primed mice. The presence of the various fractions in crude extracts of sow ovaries was monitored with the polyacrylamide gel system on days 40, 70 and 100 of pregnancy. Both the total amount and the relative proportions of the fractions were found to change as pregnancy progressed.