Characterization and Hormonal Regulation of the Progesterone Receptor in the Endometrium and Myometrium of the Rabbit
Loading...
Authors
Halstead, Julie A.
Issue Date
1979
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Through much research it is now evident that steroid hormones
interact with specific receptors in the cytoplasm of target tissues
(Chan and 0'Malley, 1976). Furthermore, it has been shown that the
steroid-receptor interaction is a prerequisite for the elicitation of
a hormonal response. Progesterone, a female sex steroid hormone, has
the primary function of preparing the uterus for blastocyst implantation
and inhibiting uterine contractions in early pregnancy. The
fact that progesterone plays such an indispensable role in early
pregnancy implies that the elimination of the binding of progesterone
with its cytoplasmic receptor might lead to a good method of fertility
control. Current research is focusing on this area with attempts
to discover an antiprogestin which has the capacity to bind to the
specific progesterone receptors with high affinity, but which does
not elicit the hormonal response characteristic of progesterone.
Studies have been done with this end in mind using cytoplasmic
progesterone receptors isolated from the entire uterus of various
experimental animals. Uncertainty prevails however, as to whether
the progesterone receptors are the same in the endometrial and myometrial
tissues of the uterus. The importance of determining whether
the progesterone receptors are similar in these two tissues lies in
the fact that if the receptors are found to have different characteristics,
one antiprogestin might not make an effective contraceptive
agent, since in order to be totally effective this agent must
suppress the progesterone response in both tissues of the uterus.
The experiments which are dealt with in this paper were designed
to discover if the specific cytoplasmic progesterone receptors in
the endometrium and myometrium of the rabbit uterus are the same 1) in terms of their affinity for both natural and synthetic steroids,
and 2) in terms of their hormonal regulation. An attempt was also
made to determine what kind of steroid configuration contributes to
an effective steroid-receptor interaction.
The studies revealed that the progesterone receptors found in
the endometrium and myometrium of rabbits are very similar in terms
of their affinity for steroids. Furthermore, it was discovered that
the steroid configuration which is best for binding has some sort of
nonpolar carbon side group of limited size at C-17, no methyl group
at C-10, and an A-ring with a ketone at C-3, a double bond at C-4,
and no other additions. In terms of hormonal regulation the results
showed that the progesterone receptors of the endometrium and myometrium
are, in general, under the same dual hormonal regulation whereby
estrogen causes an increase in receptor concentration and progesterone
has the opposite effect. More specifically however, the progesterone
receptors found in the endometrium appear to be regulated
to a greater extent by estrogen and progesterone than the progesterone
receptors in the myometrium.
With honors.
With honors.
Description
v, 67 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.