Subcellular Compartmentalization of the Progesterone Receptor in

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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