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Title:The Roles of Relaxin, Estrogen and Progesterone on Growth and Remodeling of the Cervix and Mammary Glands in the Gilt
Author(s):Winn, Robert James
Doctoral Committee Chair(s):Sherwood, O. David
Department / Program:Physiology and Biophysics
Discipline:Physiology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Biology, Animal Physiology
Biophysics, General
Abstract:We recently described relaxin-induced changes in physical and biochemical properties of the cervix that occur during the last third of the 115-day gestation period in the gilt. Histological changes in the cervix that occur between days 80 and 110 of pregnancy and the effects of relaxin on those changes were examined using morphometric analysis. Cervices obtained on day 110 differed markedly from those obtained on day 80; collagen and smooth muscle fiber bundles were less dense and lacked organization and there was an increase in amorphous ground substance. Those changes were found to be relaxin-dependent. We concluded that the relaxin-dependent changes in the histological characteristics of the cervix may contribute to the cervical softening that occurs during late pregnancy in gilts.
The growth and softening of the cervix and development of the mammary gland that occurs during the last third of gestation are temporally correlated with elevated blood levels of estrogen and progesterone as well as relaxin. The roles of those hormones on cervical growth and remodeling and mammary development remain poorly understood. Studies were conducted to examine the influence of those hormones individually and in combination on cervical growth and remodeling and mammary gland development in ovariectomized nonpregnant gilts. In the cervix, relaxin increased growth and remodeling and relaxin's effects on remodeling were markedly augmented by progesterone. Estrogen increased cervical growth, had little effect on softening and did not augment relaxin's effects on growth or softening. This study demonstrates that estrogen and relaxin act independently to promote growth of the cervix. Progesterone acts in concert with relaxin to promote softening of the cervix and alteration of the histological characteristics.
Mammary parenchymal development was modestly stimulated by estrogen while relaxin had little effect. Combined treatment with estrogen and relaxin stimulated mammary development markedly. Progesterone had no effect on mammary development but, administered in combination with relaxin, reduced the organization of the collagen fibrils of the mammary stroma. This study demonstrates that relaxin acts in concert with estrogen to stimulate development of the mammary parenchyma and acts in concert with progesterone to decrease the organization of the collagen matrix surrounding the growing mammary gland.
Issue Date:1994
Type:Text
Description:153 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1994.
URI:http://hdl.handle.net/2142/71460
Other Identifier(s):(UMI)AAI9503353
Date Available in IDEALS:2014-12-16
Date Deposited:1994


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