News Release

Ovarian Hormone Could Play Key Role In Easier, Safer Childbirth

Peer-Reviewed Publication

University of Illinois at Urbana-Champaign, News Bureau

CHAMPAIGN, Ill. -- The ovarian hormone relaxin, already in final clinical testing for the treatment of an often fatal connective-tissue disease, may have another important therapeutic role -- enabling easier and safer childbirth when labor is induced, says a researcher who reports a series of significant findings on relaxin's effects on the cervix in humans and rats.

In the October issue of the journal Biology of Reproduction, a team led by O. David Sherwood of the College of Medicine at the University of Illinois at Urbana-Champaign documented that relaxin binds to cells in the human cervix. Because it binds to the same kinds of cells in rats and pigs -- where relaxin has promoted dramatic growth and softening of the cervix during pregnancy -- the findings "encourage the view that relaxin has similar effects in the human cervix," Sherwood said.

In a separate article in the journal, relaxin was shown to promote cervical softening in pregnant rats by reducing the organization of collagen fibers in cervical connective tissue, according to work done by Sherwood and Enrique H. Luque of the Universidad Nacional del Litoral in Santa Fe, Argentina.

In September's issue of Endocrinology, Sherwood reported that relaxin promotes an increase in cervical cells in pregnant rats, providing evidence that relaxin-induced cell division contributes to cervical growth in pregnancy. Earlier this year, Sherwood disproved a widely held theory that relaxin's effects on the rat cervix are mediated by prostaglandlins, a class of signal molecules.

The flurry of published work -- funded by the National Institutes of Health -- comes as Sherwood begins his 30th year of research on relaxin. He began by isolating relaxin from rats and pigs, and finding that its structure is similar to that of insulin. Then, after determining that relaxin is secreted into the blood in the last half of pregnancy in both species, he identified its physiological roles. In addition to its effects on the cervix, relaxin prepares mother rats and pigs for nursing their young by promoting the development of the mammary glands and nipples, Sherwood's team discovered.

Sherwood is now working to understand how relaxin brings about its effects on the cervix and to explore its potential as a cervical softening agent in labor induction. In pregnant women, relaxin is found in lower amounts in the blood than in rats and pigs.

"In the human, it may be that relaxin doesn't play the vital role in remodeling the cervix that it has in rats and pigs," he said. "This possibility does not preclude relaxin's being important in a clinical perspective. As long as it has the capacity to promote growth and/or softening of the human cervix, relaxin can be brought in as a therapeutic tool during late pregnancy to soften the cervix. The key is delivering relaxin by a means that assures that it enters the bloodstream."

Initial clinical trials being conducted by Connectics Corp. of Palo Alto, Calif., have indicated that genetically engineered human relaxin softens affected skin in people suffering from scleroderma, a disease characterized by an increase in collagen fibers in the skin.

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