Subcellular. Compartmentalization of the Progesterone. Receptor in Cat Uteri Following the Acute Administration of Progesterone'. HAROLD. G. VERHAGE,2.
BIOLOGY
OF
REPRODUCTION
Subcellular in Cat Uteri
28,
545-550
(1983)
Compartmentalization Following the Acute HAROLD MARY
of the Progesterone Receptor Administration of Progesterone’
G. VERHAGE,2 K. MURRAY
Departments
and
ROBERT RANDAL
of Obstetrics
A. BOOMSMA, C. JAFFE
and
Gynecology
and
Physiology University
and
of Illinois
Biophysics
at the
Chicago,
Medical
Illinois
Center
60680
ABSTRACT cytosol and nuclear progesterone receptors in the cat uterus were measured by Scatchard analysis to determine the relationships between dose of progesterone administered and the time following administration with the content of receptor in these two cellular compartments. Cats were ovariectomized, treated for 7 days with estradiol and then injected via the saphenous vein with progesterone. One uterine horn was removed prior to, and the other uterine horn after the injection of progesterone. The amount of cytosol receptor translocated was found to be dosedependent over the range of 0-200 pg of progesterone. A maximum of 40% of the cytosol receptor was depleted even when the amount of progesterone injected was increased. In non-estradiolprimed animals it was also found that approximately 40% of the cytosol receptor was depleted following a progesterone injection. Within 3 h of the injection of 300 pg of progesterone, the cytosol and nuclear receptor levels had returned to preinjection values. A second administration of progesterone at 1 or 3 h after the first injection of progesterone caused a partial depletion of the cytosol receptor and an increase in nuclear progesterone receptor concentration. These data suggest that the translocation of cytosol receptor and the appearance of nuclear receptor is dosedependent until approximately 40% of the cytosol receptor is depleted following a single injection of progesterone, short duration
that the retention (. -... oq.
the
0
induced
))
depleted.
A
translocation rats (Walters and Leavitt,
(Fig.
5).
HOURS
the nuclear coma second increase
5).
sites
seems
dose-dependent,
limited
of
PcR
which
is unable
to undergo
of
concentrations animals whose
receptor compartmentalization Each value represents the dividual determinations from
mean three
is
shown SEM animals. ±
(nglml) subcellular in of
Fig. the
P (ng/ml)
Time
4. in-
lh 3h 6h 12h
mm
16.9 ± 3.2 8.9±1.8 3.2±1.0 2.1±0.8 0.9±0.2
percentage
in equivalent
receptors
exist:
the
of
E2-primed but the
translocated animals.
PcR
ovariectomized and the whether
and total
was
This
PcR
found
animals
much
conclusion
present
P
was cats in these
again, P induced imately 40% of the were not surprising
in non-E2
(Boomsma
PcR induced by one of these
locatable, ovariectomized
is
administered to determine animals
to
response
1982) To
not
test trans-
nonprimed whether the
could
be depleted:
the depletion available PcR. since we have
progestational
-primed,
et al.,
E2 treatment. pools was
in the cat uterus by the nonprimed ovariectomized et al., 1982), suggesting
of approxThese results shown that a can
be induced
administration of P to animals (Boomsma translocation must
occur. Thus these two pools do not account for the failure to totally deplete PcR following the acute administration of P. It is still possible, however, that there are two pools of PcR and that
10
the
unknown that the binding
also supported by direct in vitro studies of nuclear binding which generally demonstrate a nonsaturability of nuclear binding sites (Chamness et al., 1974). Two different pools of PcR
typical TABLE 1. Serum progesterone determined by RIA for the
since
PcR translocated animals was in E2-primed
could
nuclear
some other The possibility number of nuclear
unlikely
available nonprimed number
process has been described for and Clark, 1978), hamsters (Chen 1979), rabbits (Isomaa et al.,
to
or
mechanism. is in the
limitation
The
1979), and guinea pigs (Saffran and Loeser, 1980). The failure to totally deplete PcR, even with excessive doses of P, could be due to a limited number of nuclear binding sites, to a pool
/b-
FIG. 4. Subcellular distribution of PcR and PnR. E, -primed animals were injected with a single 300pg dose of P at time zero. The zero time values are the same as those shown in Fig. 1 except that the results are expressed as pmol/mg protein. The data is expressed as mean ± SEM. The number of determinations is shown in parentheses.
control
was found to be dose-dethe cat uterus, and maximal 40% of the PcR had been similar
‘
translocation,
significant P admin-
DISCUSSION Translocation
20
Nuclei.
-05
greater
pendent within when approximately
Cytosols
I
and the 10 mm
Progesterone of a before
S
C
just
of P, removed
translocation the PcR present
(Fig.
and
hysterectomized
injection.
P levels
to
E2-primed
experiment
injection horn was
both
injection
PcR was biologthe cell entered a
in
were
the immediate proportion of
first
to
animals
before the contralateral
the
replenished whether
-
30
of
P was pheral In jection
determine if ically active
.5
of PcR; had also
This decrease in in cytosol binding
acute
40
from
there
recovery of PcR
ET AL.
equal
are found tissue. This description
chick The
proportions
of
both in concept
E2-primed is supported
of
oviduct
two
forms
(Dougherty
replenishment
of
translocatable
of and PcR
PcR’s
and nonprimed by the recent 8 S p receptor Toft, 1982). and
the
loss
in of
PROGESTERONE
RECEPTORS
IN CAT
guinea
pig
a’ .E
1.5
10
Loeser, declined in
Om
the
rabbit
of
h of
observed
given
at
(Saffran
the levels of PnR values within 1 h,
cat,
(Chen et al.,
P.
24
1 mg/kg
not
P was
and
1979)
and Loeser, 1980) control levels until of
at
of
hamster
(Isomaa
administration
4-
occurred
was
mg/kg
1980). In the to premnjection
pig (Saffran returned to
I
had
administration
replenishment
h when
1979),
1.0
s.c.
24
whereas
-0. 0
the
P; however and had
.
549
replenishment
following
C
UTERI
Leavitt,
and
guinea
the PnR had 6-8 h after
It is difficult
to
not the
compare
>#{176}-
0.
the studies in results because
0.5
amounts Additionally,
these other species with of the different methods
of
P
that were is difficult
it
whether the effects to physiological or
z
observed
administered. to determine by
are due
others
pharmacological
levels
since serum levels of the hormone reported. The longer retention time
3.0
for
the
hamster
(Chan
guinea pig (Saffran due to the s.c.
2.0
1.0 E ‘U-
presumably, levels of
P to
it
was
observed
also
and
Leavitt,
and Loeser, administration
takes plateau.
the
rabbit
1979) where P was the dose administered
administered to each
30-40
than
times
greater
of
P
were not reported 1979)
and
1980) may be of P where,
more time A longer in
our and
in the
for the retention
serum time
(Isomaa
et
al.,
i.v.; however animal was present
study.
a,
C 0
In our study, were determined
30
I-
a, 4-
receptor
01 a,
180
serum levels i.v. injection very rapidly.
190
Minutes FIG. 5. Subcellular distribution of PcR and PnR before and after a second 300- Mg injection of P. E,-primed animals were first injected with 300 pg of P at time zero, and again at either 60 min or 180 mm. One uterine horn was removed just before the second P injection, and the contralateral uterine horn was removed 10 mm after the second injection of P. The data is expressed as mean ± SEM. The number at the base of each bar represents the number of individual determinations. P
