scholarly journals The oestrogen receptor in the rat uterus in relation to intra-uterine devices and the oestrous cycle

1978 ◽  
Vol 176 (2) ◽  
pp. 523-529 ◽  
Author(s):  
L Myatt ◽  
G Chaudhuri ◽  
M G Elder ◽  
L Lim
Keyword(s):  
Nuclear Receptor ◽  
Oestrogen Receptor ◽  
Dissociation Constants ◽  
Intrauterine Device ◽  
Oestrous Cycle ◽  
Rat Uterus ◽  
Receptor Complexes ◽  
Wet Weight ◽  
Cytosolic Receptor

We investigated the binding characteristics, content and intracellular distribution of nuclear and cytosolic oestrogen receptors in the uteri of rats bearing a unilateral intrauterine device, fitted 14–18 days earlier, at four phases of a 5-day oestrous cycle. The patterns of changes in wet weight and content of cytosolic and nuclear receptor that normally occur during the oestrous cycle were not altered by the presence of the device. At all stages of the cycle the intra-uterine-device-containing horn had a greater wet weight and a correspondingly higher content of cytosolic receptor than its contralateral control horn, the cellular concentration of cytosolic receptor being apparently maintained. However, the intra-uterine-device-containing horn had significantly lower cellular concentrations (i.e. per mg of DNA) of nuclear receptor, particularly at late dioestrus and pro-oestrus. Thus the treated horn showed a decreased translocation of receptor in response to increases in circulating oestrogens. Both horns contained equivalent amounts of an activating factor implicated in translocation and measured in vitro by binding of cytosol receptor to oligo(dT)-cellulose. The presence of an intra-uterine device neither altered the dissociation constants (Kd) of the nuclear and cytosolic oestrogen-receptor complexes nor the stability of the nuclear receptor complex in vitro. The decreased translocation cannot thus be directly attributed to changes in the physical properties of the receptor. This decrease may be responsible for the anti-fertility effect of the intra-uterine device (which affects only the treated horn of the bicornuate rat uterus), since implantation of the blastocyst requires correct concentrations of nuclear oestrogen receptor.

ALTERATIONS IN PROGESTERONE RECEPTORS IN THE RAT UTERUS BEARING AN INTRA-UTERINE DEVICE DURING THE OESTROUS CYCLE AND EARLY PREGNANCY

1980 ◽  
Vol 87 (3) ◽  
pp. 365-373 ◽  
Author(s):  
LESLIE MYATT ◽  
M. G. ELDER ◽  
LOUIS LIM
Keyword(s):  
Progesterone Receptor ◽  
Nuclear Receptor ◽  
Early Pregnancy ◽  
Dissociation Constants ◽  
Progesterone Receptors ◽  
Oestrous Cycle ◽  
Rat Uterus ◽  
Binding Characteristics ◽  
Receptor Complexes ◽  
And Control

The binding characteristics, content and intracellular distribution of cytosolic and nuclear progesterone receptors have been investigated, using [3H]progesterone as ligand, in the rat uterus bearing a unilateral intra-uterine device (IUD) during the oestrous cycle and from days 3 to 6 of pregnancy. The dissociation constants of nuclear and cytosolic progesterone–receptor complexes for IUD-containing and control uterine horns were similar. Cytosolic receptor concentrations in the IUD-containing uterus were always lower but changed in a manner similar to the control during the periods studied. Nuclear receptor concentrations in the control horn reflected changes in hormone levels during the oestrous cycle although concentrations measured were greater than previously reported. However, in IUD-containing uteri the pattern was completely reversed with minimal levels at pro-oestrus. Nuclear receptor concentrations were little different in both horns during early pregnancy. Total progesterone receptor synthesis determined between metoestrus and pro-oestrus in IUD-containing horns was significantly less than that of control horns. This correlated with the attenuated rise of nuclear oestrogen receptor levels previously observed between these times in IUD-containing uterine horns.

Effect of theophylline on nuclear retention of oestrogen-receptor complexes: correlation with oestrogen responses

1985 ◽  
Vol 105 (3) ◽  
pp. 397-403
Author(s):  
J. Steinsapir ◽  
A. M. Rojas ◽  
M. E. Bruzzone ◽  
A. White ◽  
O. Alarcón ◽  
...  
Keyword(s):  
Body Weight ◽  
Oestrogen Receptor ◽  
Nuclear Retention ◽  
Adult Rat ◽  
Receptor Complexes ◽  
Wet Weight

ABSTRACT In the ovariectomized adult rat uterine oedema induced by 0·01 and 0·1 μg oestradiol-17β/100 g body weight increased further in the presence of theophylline. Nuclear retention of oestrogen-receptor complexes also increased in response to theophylline both in vivo and in vitro. Theophylline decreased the number of eosinophils in the blood and concurrently decreased oestrogen-induced uterine eosinophilia at doses of 0·001, 0·01, 0·1, 1, 10 or 30 μg oestradiol/100 g body weight, through a mechanism independent of glucocorticoids. There was, therefore, no correlation between changes in the number of uterine eosinophils and changes in uterine wet weight induced by theophylline and oestrogen. It is suggested that the presence of oestrogen-receptor complexes in the nucleus for at least 4 h is a prerequisite for the induction of uterine oedema and growth in the presence of theophylline and oestradiol-17β. J. Endocr. (1985) 105, 397–403

EFFECT OF AN INTRA-UTERINE DEVICE ON INTRACELLULAR RELATIONSHIPS OF THE UTERINE OESTROGEN RECEPTOR, PARTICULARLY DURING PREGNANCY

1980 ◽  
Vol 87 (3) ◽  
pp. 357-364 ◽  
Author(s):  
LESLIE MYATT ◽  
GAUTAM CHAUDHURI ◽  
M. G. ELDER ◽  
LOUIS LIM
Keyword(s):  
Protein Synthesis ◽  
Nuclear Receptor ◽  
Oestrogen Receptor ◽  
Oestrous Cycle ◽  
Blastocyst Implantation ◽  
High Concentrations ◽  
Cyclic Changes ◽  
And Control ◽  
Nuclear Content

The presence of an intra-uterine device in the rat results in a lower nuclear concentration of the oestrogen receptor in the treated horn at pro-oestrus when it is compared with the contralateral control horn. This effect was also seen after the administration of hyperphysiological doses of oestradiol and when the horn was exposed in vitro to high concentrations of oestradiol. The cyclic changes during the oestrous cycle in the activity of the oestrogen-induced enzyme peroxidase were similar in the treated and control horns. These observations have discounted the possibility that the relatively lower nuclear receptor content in the treated horn at pro-oestrus was due to a decreased exposure to oestrogen. A significantly lower nuclear content was also observed in the treated horn on days 4 and 5 of pregnancy. This was not associated with a deficiency in cytosol receptor content which increased concurrently with that of the control horn in the 6 days of pregnancy that were studied. The proportional content of the putative cytosol factor implicated in receptor translocation was similar in both horns, increasing on days 4 and 6 in concert with reported changes in 'induced protein' synthesis. There appeared to be reduced levels of nuclear receptor at a time when blastocyst implantation normally occurs.

scholarly journals The unoccupied nuclear oestradiol receptor in the rat uterus and hypothalamus during the oestrous cycle

1981 ◽  
Vol 194 (3) ◽  
pp. 667-671 ◽  
Author(s):  
S Thrower ◽  
C Neethling ◽  
J O White ◽  
L Lim
Keyword(s):  
Nuclear Receptor ◽  
Oestrogen Receptor ◽  
Oestrous Cycle ◽  
Oestrogen Receptors ◽  
Rat Uterus ◽  
Immature Rat ◽  
High Affinity ◽  
Receptor Component ◽  
Cyclic Changes

The nuclear oestrogen receptor population in the rat uterus contained an unoccupied receptor component that bound oestradiol with the high affinity (Kd congruent to 0.5 nM) characteristic of oestrogen receptors. This unoccupied receptor was present at all phases of the oestrous cycle. Its content changed in parallel with that of the total nuclear receptor during the cycle. Oestradiol administration to the immature rat resulted in increases in the uterine content of long-term nuclear receptors (i.e., those still present 8 h after administration); these increases were due to occupied oestrogen receptors, since the content of unoccupied receptor was unchanged. Our previous experiments [White & Lim (1980) Biochem. J. 190, 833-837] have shown in contrast, that oestradiol administration results in an increase in the content of unoccupied nuclear receptor in the hypothalamus. However, as in the uterus, similar cyclic changes in the content of unoccupied nuclear receptor occurred in parallel with those of the total nuclear receptor population in the hypothalamus. Differences and similarities between the unoccupied nuclear receptor of the uterus and hypothalamus are briefly discussed.

scholarly journals Intracellular relationships of the oestrogen receptor in the rat uterus and hypothalamus during the oestrous cycle

1978 ◽  
Vol 172 (1) ◽  
pp. 37-47 ◽  
Author(s):  
J O White ◽  
S Thrower ◽  
L Lim
Keyword(s):  
Oestrogen Receptor ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Nuclear Binding ◽  
Age Related ◽  
Wet Weight ◽  
Cyclic Changes ◽  
Nuclear Content

Simultaneous measurements were made of the specific oestrogen receptor in the nuclear and cytosol fractions prepared from the uterus and hypothalamus of 50–81-day-old female rats undergoing a 4-day oestrous cycle. In the uterus, the content of nuclear receptor fluctuated in concert with known cyclic changes in the secretion of oestrogen, being maximal at pro-oestrus. Over the period of 50–81 days, the nuclear content at all phases increased with age, again corresponding to known age-related increases in ovarian secretion of oestrogen. This age-related increase in nuclear content, averaged from the values of the different phases in each age group, was related to equivalent increases in uterine wet weight, an increase of 1 pmol of receptor being accompanied by an increase of 80–90 mg. The concentration of cytosol receptor was maintained constant, with respect to wet weight, throughout the cycle and with age, irrespective of changes in nuclear content. In the uterus of normal mature females, translocation of receptor into the nucleus did not lead to depletion of cytosol receptor, suggesting a process of continuous replenishment/synthesis. In the hypothalamus, the nuclear content of oestrogen receptor was also maximal at pro-oestrus. In contrast with the uterus, the content of hypothalamic cytosol receptor was minimal at this phase and reflects depletion of the cytosol receptor, possibly as a result of translocation. The extent of translocation was low compared with that in the uterus and did not alter with age during the age-period studied. This low nuclear binding of the receptor in vivo is discussed in relation to the presence of a cytosol factor, present in limiting amounts, which in vitro mediates the binding of cytosol receptor to oligo(dT)-cellulose. The difference in the physiological response of the uterus and of the hypothalamus to oestrogens may be related to the extent of nuclear binding of receptor.

Properties and ontogeny of the glucocorticoid receptor in the placenta and fetal lung of the sheep

1984 ◽  
Vol 103 (1) ◽  
pp. 31-42 ◽  
Author(s):  
A. P. F. Flint ◽  
R. D. Burton
Keyword(s):  
Glucocorticoid Receptor ◽  
Glucocorticoid Receptors ◽  
Dissociation Constants ◽  
Specific Binding ◽  
Gel Filtration ◽  
Fetal Lung ◽  
Maternal Circulation ◽  
Whole Cell ◽  
Cytosolic Receptor

ABSTRACT The cytosolic glucocorticoid receptor of ovine placental zona intima has been characterized and measured between day 51 of pregnancy and term, and levels compared with those in fetal lung. By ion-exchange and gel-filtration chromatography the molybdate-stabilized receptor was found to be an acidic molecule with Stokes radius approximately 8 nm; these physicochemical characteristics of the ovine placental receptor are comparable to those of receptors in glucocorticoid target tissues from non-ruminants. Concentrations of cytosolic receptor in placenta (mean, 139 fmol/mg protein) were lower than those in fetal lung (627 fmol/mg) at all stages of gestation investigated. To some extent this difference was accounted for by a twofold higher concentration of protein in placental cytosols compared with those from fetal lung. In both tissues, cytosolic receptor concentrations were maximal between days 91 and 130, when fetal adrenal steroid secretion is low; receptor concentrations decreased before term. Fetal hypophysectomy, which resulted in prolonged gestation, raised receptor concentrations in placenta, but not in fetal lung. In both tissues, apparent dissociation constants for [3H]dexamethasone binding to glucocorticoid receptors were in the range 0·5–7·1 nmol/l; these dissociation constants did not change consistently between day 100 and term. In whole-cell preparations of placenta and fetal lung incubated in vitro there was time-dependent specific binding of [3H]dexamethasone by nuclei, and binding of labelled cytosolic receptor to isolated nuclei occurred at all stages of gestation investigated. Binding of [3H]dexamethasone by cytosolic receptor from placenta and fetal lung was inhibited by progesterone and 17α-hydroxyprogesterone, as well as by cortisol, cortisone, 11-deoxycorticosterone and 11β-hydroxyprogesterone; 20α-hydroxyprogesterone and 17α,20α-dihydroxypregn-4-en-3-one were less effective. In experiments to evaluate the possible antagonistic action of progesterone in whole-cell preparations, uptake of [3H]dexamethasone by nuclei was increased up to twofold in placental minces incubated with aminoglutethimide or epostane, when progesterone synthesis was reduced by 98 and 92 per cent respectively. Nuclear uptake in minces of fetal lung was blocked by concentrations of progesterone found in placenta. The existence of a placental glucocorticoid receptor confirms that fetal cortisol may act directly on the placenta to induce the enzymatic changes controlling the onset of labour. Its availability early in pregnancy is consistent with the ability of administered glucocorticoid to induce labour at any time after day 90 of gestation. Progesterone in the placenta may act as a glucocorticoid antagonist, protecting the fetus against inappropriate induction of preterm labour resulting from high levels of glucocorticoids in the maternal circulation. J. Endocr. (1984) 103, 31–42

A HIGH-AFFINITY BINDING SITE FOR THE ANTIOESTROGENS, TAMOXIFEN AND CI 628, IN IMMATURE RAT UTERINE CYTOSOL WHICH IS DISTINCT FROM THE OESTROGEN RECEPTOR

1981 ◽  
Vol 91 (1) ◽  
pp. 155-161 ◽  
Author(s):  
L. C. MURPHY ◽  
R. L. SUTHERLAND
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Oestrogen Receptor ◽  
Dissociation Constants ◽  
Significant Proportion ◽  
Immature Rat ◽  
High Affinity ◽  
Saturable Binding ◽  
Receptor Sites

A high-affinity, saturable antioestrogen binding site, which does not bind oestradiol, has been reported to exist in a number of oestrogen target tissues but not in the immature rat uterus. This study reports the results of a more thorough search for this site in immature rat uterine cytosol. When concentrations of uterine cytoplasmic oestrogen receptor were selectively depleted by translocation of 90–95% of the cytoplasmic oestrogen receptor to the nucleus, saturation analysis studies revealed that the antioestrogens, tamoxifen and CI 628, were bound to high-affinity, saturable binding sites which were present at about 2·5 times the concentration of the residual oestrogen receptor sites. Oestradiol could only partially inhibit the binding of tritiated antioestrogens to their saturable binding sites in this material indicating that a significant proportion of these sites were distinct from the oestrogen receptor sites. This was confirmed in experiments where oestrogen receptor sites were saturated in vitro with oestradiol and high-affinity, saturable sites for CI 628 and tamoxifen were still present. The CI 628 and tamoxifen had high affinity for these sites with dissociation constants of 1·0–1·6 nmol/l. These specific antioestrogen binding sites were present at about 5% of the concentration of oestrogen receptors in normal immature rat uterine cytosol which probably explains their previous lack of detection in this material.

scholarly journals Interaction of nistranol with estradiol and progesterone receptors in the rat uterus cytosol in vitro and in vivo

1996 ◽  
Vol 42 (4) ◽  
pp. 33-34
Author(s):  
Ye. N. Kareva ◽  
V. P. Fedotov ◽  
V. M. Rzheznikov ◽  
Ye. V. Solovyova ◽  
Ye. V. Pokrovskaya
Keyword(s):  
Single Injection ◽  
Progesterone Receptors ◽  
Uterine Tissue ◽  
Rat Uterus ◽  
Cytosol Fraction ◽  
Receptor Complexes ◽  
Target Organs ◽  
Uterine Growth

Interactions between nistranol and estradiol and progesterone receptors in the cytosol fraction of the uterine tissue of oophorectomized rats and the relative competitive capacity of nistranol have been studied 24 h after a single injection of the drug. The results demonstrate the effects of nistranol on estradiol and progesterone binding. Nistranol boosting of uterine growth in rats is explained by its capacity to accelerate the translocation of hor- mone-receptor complexes into the nucleus. Investigations of the capacity of new estrogens to compete with estradiol for binding in the tissues of target organs in vitro and affect estradiol and progesterone binding in vivo permit a more effective screening of estrogens than use of only the classical in vitro method.

Studies on the activation of the oestrogen receptor bound to the anti-oestrogens 4-hydroxytamoxifen and ICI 164,384 by using three monoclonal antibodies

1991 ◽  
Vol 7 (1) ◽  
pp. 9-19 ◽  
Author(s):  
N. Giambiagi ◽  
J. R. Pasqualini
Keyword(s):  
Monoclonal Antibodies ◽  
Guinea Pig ◽  
Nuclear Receptor ◽  
Structural Transformation ◽  
Oestrogen Receptor ◽  
The Other ◽  
Receptor Complex ◽  
Intact Cells ◽  
Receptor Dimerization ◽  
Receptor Complexes

ABSTRACT Three monoclonal antibodies, H222, H226 and D547, which provided evidence of the structural transformation and change in exposure of the functional domains of the oestrogen receptor from fetal guineapig uterus upon activation, were used to study the receptor bound to the anti-oestrogens 4-hydroxytamoxifen and ICI 164,384. No differences in the structure of non-activated 4-hydroxytamoxifen— and ICI 164,384—receptor complexes, as compared with the oestradiol—receptor complex, were detected by the three monoclonal antibodies. When heated at 28°C, both anti-oestrogen—receptor complexes became capable of binding the D547 antibody, which reacts selectively with the activated receptor; however, this binding was lower than that of the oestradiol-receptor complex. The interaction with the H226 antibody showed that anti-oestrogens can induce receptor dimerization, but to a lesser extent than oestradiol. In addition, both anti-oestrogen—receptor complexes can bind to DNA—cellulose and are retained in nuclei from intact cells at 28°C, but less efficiently than the oestradiol—receptor complex. On the other hand, the nuclear receptor seems to have a similar dimeric structure when bound to either anti-oestrogens or oestradiol, as detected by the three monoclonal antibodies. The data suggest that 4-hydroxytamoxifen and ICI 164,384 induce an impaired activation of the oestrogen receptor; this difference, although quantitative rather than qualitative, might be related to the partial agonistic action of these anti-oestrogens in the fetal guinea-pig uterus.

scholarly journals Acceptor sites for the oestrogen receptor in hen oviduct chromatin

1983 ◽  
Vol 210 (3) ◽  
pp. 905-912 ◽  
Author(s):  
T S Ruh ◽  
T C Spelsberg
Keyword(s):  
Receptor Binding ◽  
Oestrogen Receptor ◽  
Guanidine Hydrochloride ◽  
Scatchard Analysis ◽  
Oestrogen Receptors ◽  
Receptor Complexes ◽  
High Affinity ◽  
Acceptor Activity ◽  
Specificity Of Binding

Partially purified hen oviduct oestrogen receptors, charged with [3H]oestradiol, were shown to specifically bind in vitro to purified hen oviduct chromatin. Maximal binding occurred within 60min at 0 degrees C in a Tris buffer containing 0.1 M-KCl and 0.5 mM-phenylmethanesulphonyl fluoride. The binding of the [3H]oestradiol-receptor complexes to intact purified chromatin was saturable, whereas the receptor binding to hen DNA remained linear. Saturation was further demonstrated by the minimal acceptor binding of receptor charged with [3H]oestradiol plus 200-fold oestradiol compared with [3H]oestradiol receptors at equal [3H]oestradiol concentrations. Scatchard analysis of [3H]oestradiol-receptor binding to chromatin above DNA levels gave indications of high-affinity binding with a low capacity. Further, the nuclear binding was tissue-specific since the binding to hen spleen chromatin was negligible. To further uncover the specific acceptor sites, proteins were removed from hen oviduct chromatin by increasing concentrations of guanidine hydrochloride (1-7M). Those residual fractions extracted with 3-7 M-guanidine hydrochloride had the highest acceptor activity (above DNA levels) with the peak activity uncovered by 5 M-guanidine hydrochloride. To further characterize the oestrogen-receptor acceptor sites, oviduct chromatin was bound to hydroxyapatite in the presence of 3 M-NaCl and then protein fractions were extracted sequentially with 1-7 M-guanidine hydrochloride. Each fraction was then reconstituted to pure hen DNA by reverse gradient dialysis. [3H]Oestradiol receptors were found to bind to the greatest degree to the fraction reconstituted from the 5 M-guanidine hydrochloride protein extract. Reconstituted nucleoacidic proteins (NAP) from combined 4-7 M-guanidine hydrochloride protein extracts showed saturable binding by [3H]-oestradiol receptors, whereas binding to hen DNA did not saturate. The high affinity, low capacity, and specificity of binding of oestrogen receptors to NAP was similar to that found in intact chromatin. Thus, chromatin acceptor proteins for the oestrogen receptor have been partially isolated and characterized in the hen oviduct and display properties similar to that reported for the acceptor proteins of the progesterone receptor.

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