Regulation of Serum and Ovarian Relaxin Levels and Corpus Luteum Function During the Second Half of Pregnancy in the Rat (Ovary, Birth, Gestation)
Golos, Thaddeus Gerard
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/71431
Description
Title
Regulation of Serum and Ovarian Relaxin Levels and Corpus Luteum Function During the Second Half of Pregnancy in the Rat (Ovary, Birth, Gestation)
Author(s)
Golos, Thaddeus Gerard
Issue Date
1984
Department of Study
Physiology and Biophysics
Discipline
Physiology
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Animal Physiology
Abstract
The studies presented in this thesis were conducted to investigate the regulation of relaxin synthesis and secretion by the ovary from days 12 to 20 of pregnancy in the rat (Phase I). Initial immunocytochemical studies utilizing a specific rabbit anti-rat relaxin serum demonstrated that the cells of the corpus luteum (CL) are the only source of relaxin in the pregnant rat. The role of the conceptus in regulating relaxin synthesis and secretion was examined by investigating the effects of conceptus number on serum and ovarian relaxin levels, as well as on serum progesterone (P4) levels and CL weights. A direct relationship between the number of conceptuses and the rate and/or degree of increase in these parameters during Phase I was demonstrated. Additionally, it was shown that the placenta but not the fetus is responsible for maintaining elevated relaxin levels. The influence of the maternal pituitary on CL function during Phase I was then investigated. While rats bearing one conceptus had markedly reduced serum and luteal relaxin levels, serum P4 levels, and CL weights from days 14 to 20 compared to rats bearing a full complement of > 8 conceptuses, hypophysectomy at midpregnancy restored all these parameters except luteal relaxin content to levels similar to those seen in full complement-bearing rats. These results suggest that while the placenta maintains CL function during Phase I, the pituitary has a suppressive effect on the CL. This suppressive effect of the maternal pituitary was further investigated by determining the effects of hypophysectomy on CL function in rats with CL ectopically established under the kidney capsule (eCL) in the absence of the ovary. Consistent with results obtained in rats with intact ovaries, serum relaxin levels and CL weights were lower in eCL rats with 2 conceptuses than in those with > 5 conceptuses, but were significantly increased following hypophysectomy. Serum P4 levels also tended to follow the trends observed with serum relaxin levels. It was concluded that the nonluteal portion of the ovary does not mediate the suppressive effect of the pituitary on luteal function during Phase I in pregnant rats.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
