Alternate immune system targets for TCDD: lymphocyte stem cells and extrathymic T-cell development

We here summarize evidence that thymic atrophy induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can be mediated, at least in part, by damage to extrathymic T-cell precursors in bone marrow and fetal liver. This atrophy induction does not involve apoptotic mechanisms in thymocytes affected by the bcl-2 proto-oncogene. TCDD mediates atrophy induction through its specific receptor (the AhR) and not through effects on the estrogen receptor. Both TCDD and estradiol induce extrathymic T-cell differentiation in the liver. These extrathymic T-cell populations include cells expressing elevated levels of V beta T-cell receptors that are normally deleted in thymic development.

Effect of oestradiol on dopamine receptors and protein kinase C activity in the rat pituitary: binding of oestradiol to pituitary membranes

Oestradiol exerts an important modulatory influence on the release of prolactin which is accomplished partly through disruption of the inhibitory influence of dopamine. We have focused on the status of the anterior pituitary D2 dopamine receptor in female rats treated chronically with oestradiol or progesterone. A direct membrane effect of these steroids on the dopamine system was also investigated in vitro. Both steroids affected the status of the D2 receptor, oestradiol decreasing the number of sites in vitro and progesterone increasing it both in vitro and in vivo. The in vitro studies demonstrated that these steroids exert a direct membrane effect on the D2 receptor. These results correlated with an in vitro short-term physiological effect of oestradiol and progesterone on the dopaminergic inhibition of prolactin release, oestradiol decreasing it while progesterone had the opposite effect. Binding studies with [3H] oestradiol on pituitary membranes revealed a site for oestradiol of high affinity and low capacity, indicating that oestradiol's membrane effects could be mediated by a specific receptor. In vivo treatment with oestradiol also induces proliferation of prolactin-secreting cells (lactotrophs). We focused on the effect of oestradiol on protein kinase C activity, which is involved in both secretion and proliferation. In female rats treated with oestradiol total protein kinase C activity was increased by 74% (particulate 90%, soluble 71%) in comparison with controls. This effect was reversed by concomitant treatment with a dopamine agonist. Thus in the pituitary oestradiol and progesterone affect the characteristics of membrane components that are implicated in the physiological control of the cell. Whether these effects are post-transcriptional only or are also mediated through direct membrane mechanisms needs further investigation.

Proliferative responses to altered 17beta-hydroxysteroid dehydrogenase (17HSD) type 2 expression in human breast cancer cells are dependent on endogenous expression of 17HSD type 1 and the oestradiol receptors

The primary source of oestrogen in premenopausal women is the ovary but, after menopause, oestrogen biosynthesis in peripheral tissue is the exclusive site of formation. An enzyme group that affects the availability of active oestrogens is the 17beta-hydroxysteroid dehydrogenase (17HSD) family. In breast cancer, 17HSD type 1 and type 2 have been mostly investigated and seem to be the principal 17HSD enzymes involved thus far. The question whether 17HSD type 1 or type 2 is of greatest importance in breast tumour development is still not clear. The aim of this study was to investigate how the loss of 17HSD type 2 expression, using siRNA in the non-tumour breast epithelial cells HMEC (human mammal epithelial cells) and MCF10A, and gain of 17HSD type 2 expression, using transient transfection in the breast cancer derived cell lines MCF7 and T47D, affect oestradiol conversion and proliferation rate measured as S-phase fraction. We further investigated how this was related to the endogenous expression of 17HSD type 1 and oestradiol receptors in the examined cell lines. The oestradiol level in the medium changed significantly in the MCF7 transfected cells and the siRNA-treated HMEC cells, but not in T47D or MCF10A. The S-phase fraction decreased in the 17HSD type 2-transfected MCF7 cells and the siRNA-treated HMEC cells. The results seemed to be dependent on the endogenous expression of 17HSD type 1 and the oestradiol receptors. In conclusion, we found that high or low levels of 17HSD type 2 affected the oestradiol concentration significantly. However, the response was dependent on the endogenous expression of 17HSD type 1. Expression of 17HSD type 1 seems to be dominant to 17HSD type 2. Therefore, it may be important to investigate a ratio between 17HSD type 1 and 17HSD type 2.

Membrane 5alpha-pregnane-3,20-dione (5alphaP) receptors in MCF-7 and MCF-10A breast cancer cells are up-regulated by estradiol and 5alphaP and down-regulated by the progesterone metabolites, 3alpha-dihydroprogesterone and 20alpha-dihydroprogesterone, with associated changes in cell proliferation and detachment

Previous studies have shown that the progesterone metabolite, 5alpha-pregnane-3,20-dione (5alphaP), exhibits mitogenic and metastatic activity in breast cell lines and that specific, high affinity receptors for 5alphaP are located in the plasma membrane fractions of tumorigenic (ER/PR-positive) MCF-7 cells. The aim of this study was to determine the effects of the mitogenic (estradiol; 5alphaP) and anti-mitogenic (3alpha-hydroxy-4-pregnen-20-one, 3alphaHP; 20alpha-hydroxy-4-pregnen-3-one, 20alphaHP) endogenous steroid hormones on 5alphaP receptor (5alphaP-R) numbers and on cell proliferation and adhesion of MCF-7 and MCF-10A cells. Exposure of MCF-7 cells for 24h to estradiol or 5alphaP resulted in significant (p < 0.05-0.001) dose-dependent increases in 5alphaP-R levels. Conversely, treatment with 3alphaHP or 20alphaHP resulted in significant (p < 0.05-0.01) dose-dependent decreases in 5alphaP-R levels. Treatment with one mitogenic and one anti-mitogenic hormone resulted in inhibition of the mitogen-induced increases, whereas treatment with two mitogenic or two anti-mitogenic hormones resulted in additive effects on 5alphaP-R numbers. Treatments with cycloheximide and actinomycin D indicate that changes in 5alphaP-R levels depend upon transcription and translation. The non-tumorigenic breast cell line, MCF-10A, was also shown to posses specific, high affinity plasma membrane receptors for 5alphaP that were up-regulated by estradiol and 5alphaP and down-regulated by 3alphaHP. Estradiol binding was demonstrated in MCF-10A cell membrane fractions and may explain the estradiol action in these cells that lack intracellular ER. In both MCF-7 and MCF-10A cells, the increases in 5alphaP-R due to estradiol or 5alphaP, and decreases due to 3alphaHP or 20alphaHP correlate with respective increases and decreases in cell proliferation as well as detachment. These results show distribution of 5alphaP-R in several cell types and they provide further evidence of the significance of progesterone metabolites and their novel membrane-associated receptors in breast cancer stimulation and control. The findings that 3alphaHP and 20alphaHP down-regulate 5alphaP-R and suppress mitogenic and metastatic activity suggest that these endogenous anti-mitogenic progesterone metabolites deserve considerations in designing new breast cancer therapeutic agents.

Synthesis and Biological Properties of New Stilbene Derivatives of Resveratrol as New Selective Aryl Hydrocarbon Modulators

We developed new stilbene derivatives of resveratrol (E)-1-(4'-hydroxyphenyl)-2-(3,5-dihydroxyphenyl)ethene) selective for AhR and devoid of affinity for ER. Among the 24 stilbenes synthesized, all display a higher affinity than resveratrol for AhR. (E)-1-(4'-Trifluoromethylphenyl)-2-(3,5-ditrifluoromethylphenyl)ethene (4e), (E)-1-(4'-methoxyphenyl)-2-(3,5-dichlorophenyl)ethene (4j), and (E)-1-(4'-chlorophenyl)-2-(3,5-dichlorophenyl)ethene (4b) are selective, high-affinity AhR antagonists with, respective, K(i)s of 2.1, 1.4, and 1.2 nM. (E)-1-(4'-Trifluoromethylphenyl)-2-(3,5-dichlorophenyl)ethene (4i) displays a K(i) of 0.2 nM and is a selective and high-affinity agonist on AhR.

Effects of testosterone and 17-beta-estradiol on TNF-alpha-induced E-selectin and VCAM-1 expression in endothelial cells. Analysis of the underlying receptor pathways

This study investigated the effects of testosterone and 17-beta-estradiol on tumor necrosis factor-alpha (TNF-alpha)-induced endothelial expression of E-selectin and vascular cell adhesion molecule-1 (VCAM-1) and the potential roles of hormone receptors involved in these actions. Human umbilical vein endothelial cells (HUVEC) were stimulated with TNF-alpha in the presence or absence of testosterone or 17-beta-estradiol, and the expression of E-selectin and VCAM-1 was investigated. As shown by Western blot analysis, co-administration with testosterone or 17-beta-estradiol increased the expression of E-selectin and VCAM-1 induced by TNF-alpha at 6 h and 3 h, respectively. Similarly, RT-PCR analysis revealed a significant increase in the amount of mRNA for E-selectin and VCAM-1 after co-administration with testosterone or 17-beta-estradiol in TNF-alpha-stimulated HUVEC. The presence of mRNA and proteins for androgen receptor and estrogen receptor alpha in HUVEC was verified by RT-PCR and Western blot. Flow cytometric analysis showed that preincubation with androgen receptor antagonist cyproterone and estrogen receptor antagonist tamoxifen completely abrogated the upregulating effects of testosterone and 17-beta-estradiol on TNF-alpha-induced E-selectin and VCAM-1 expression, respectively. Expression of TNF receptors in TNF-alpha-stimulated HUVEC was not influenced by testosterone and 17-beta-estradiol. The data indicate that both testosterone and 17-beta-estradiol increase TNF-alpha-induced E-selectin and VCAM-1 expression in endothelial cells via a receptor-mediated system, and expression of TNF receptors are not changed in these actions. The implications of these results for the facilitory effects of both sex hormones on immune reactions are discussed.

Neuroprotective effects of estrogens on hippocampal cells in adult female rats after status epilepticus

PURPOSE

Estrogens have neuroprotective effects in ischemia, stroke, and other conditions leading to neuronal cell death (e.g., Alzheimer's disease). The present study examined whether estrogens may have neuroprotective effects after seizures.

METHODS

The kainic acid model was used to determine if estrogens protect hippocampal cells after status epilepticus in adult female rats. Rats were ovariectomized 1 week before hormone replacement. beta-Estradiol benzoate (EB; 2 microg in 0.1 mL of oil) was injected subcutaneously 48 and 24 hours before seizure testing. We administered kainic acid (16 mg/kg intraperitoneally) and behaviorally monitored the rats for 5 hours. After this time, all rats were injected with pentobarbital (50 mg/kg intraperitoneally) irrespective of seizure severity. Some rats received two additional doses of EB, one immediately and one 24 hours after the seizures. Another group of rats received only these two doses of EB after the seizures, and yet another group of rats received pretreatment with the intracellular EB receptor antagonist tamoxifen before each of four EB injections. Control rats received oil instead of EB. Rats were killed 48 hours after seizures. Neuronal damage was evaluated in silver-impregnated and Nissl-stained sections.

RESULTS

Estrogen treatment before kainic acid administration significantly delayed the onset of kainic acid-induced clonic seizures, whereas it did not change the onset of status epilepticus compared with oil-treated controls. Furthermore, estrogen treatment significantly protected against kainic acid-induced seizure-related mortality. In control rats, examination of Nissl-stained and silver-impregnated slides revealed severe neuronal damage in the vulnerable pyramidal neurons of the hippocampal CA3 subfield and in the hilus of the dentate gyrus. Estrogen pretreatment, as well as the combination of pretreatment and posttreatment, significantly reduced the number of argyrophilic neurons in both the CA3 and the dentate gyrus. Posttreatment only had no protective effects. The data indicate that intracellular EB receptors mediate this type of neuroprotective effect, because the tamoxifen pretreatment abolished EB neuroprotection.

CONCLUSIONS

Our results suggest that estrogens can be beneficial in protecting against status epilepticus-induced hippocampal damage. Hormonal conditions may have differential effects on underlying epileptic state in some patients. Therefore, more studies are necessary to determine the prospective therapeutic advantage of hormonal treatment in seizure-related damage.

[An analysis of 3H-tamoxifen binding with the cell plasma membranes of the rat uterus]

The effect of phencarol, ranitidine, propranolol, atropine, and diethylstilbestrol (known as modulators of the tamoxifen-binding sites in plasma membranes) on the 3H-tamoxifen binding to the plasma membrane fraction of white rat uterine cells was studied by determining the amounts of estradiol and H1- and H2-receptors. The interaction of tamoxifen with various receptors of uterine cells may be significant for evaluation of the tumor activity of this compound.

Reproductive effects of hexachlorobenzene in female rats

Hexachlorobenzene (HCB) is a polyhalogenated aromatic hydrocarbon widely distributed in the environment. In animal testing, HCB has been shown to be a reproductive toxin. Previous investigations of the effects of HCB on ovarian function have yielded equivocal results. Thus, the effects of chronic administration of HCB (1 g kg(-1) body wt.) on the ovary and pituitary hormone levels, hepatic and uterine oestradiol receptors, ovarian histopathological changes and oestrus cycle characteristics were investigated in spontaneously cycling rats. Our data demonstrate that HCB treatment, under the conditions of the present study, reduced circulating levels of oestradiol and prolactin without differences in serum concentrations of progesterone. Follicle-stimulating hormone serum levels were elevated. Hexachlorobenzene treatment resulted in irregularity of cycles, characterized mainly as prolonged periods of oestrus with a reduced number of ova recovered. In addition, HCB administration resulted in significantly decreased uterine nuclear oestrogen receptor levels. Histopathological examination revealed degenerative changes of the ovarian follicles and germinal epithelium and increased numbers of atresic follicles.

In vitro responses to 17beta-estradiol throughout pubertal maturation in female human bone cells

To test the hypothesis that bone sensitivity to estrogens differ with the pubertal status, we cultured human osteoblasts (hOBs) from 14 girls (3-18 years) and examined the effects of repeated weekly doses of 17beta-estradiol (E2, 10 pM-10 nM) on estradiol receptor (ER) and progesterone receptor (PR) expression, type I procollagen (PICP) and osteocalcin (BGP; bone Gla protein) production, and alkaline phosphatase (ALP) activity. The bone samples were divided into two equal groups according to the pubertal status and plasma E2 level of the donor. The two groups were significantly different for age (9 +/- 1 and 15 +/- 1 years), pubertal status (Tanner stages I-III and IV-V), and plasma E2 concentrations (17 +/- 3 and 49 +/- 4 pg/ml). ER and PR were expressed and not influenced by the sexual maturation in untreated cells. E2 increased ER in the two groups with nanomolar doses. Picomolar doses did not significantly increase ER expression but led to significant differences in the percentage of cells expressing ER in premenarchial (33%) and postmenarchial (7%) hOB cultures. In the two groups, E2 had no clear effect on PR expression, ALP activity, nor BGP production. But repeated weekly doses of E2 significantly influenced PICP production at picomolar doses. This effect depended upon the sexual maturation of the donor. E2 decreased PICP in premenarchial cultures and increased PICP in postmenarchial cultures. Thus, E2 modulates in vitro human bone cell metabolism and probably their phenotype and has different effects, depending on the pubertal status of the donor. Unlike what could have been expected, prepubertal and early pubertal hOBs appear to be specifically sensitive to picomolar doses of E2, suggesting that this hormone is a crucial regulator of bone metabolism even before puberty.

Hormonal regulation of oestrogen and progesterone receptors in cultured bovine endometrial cells

Changes in the number of progesterone and oestradiol receptors in the endometrium are thought to play a role in the induction of luteolysis. The effect of oestradiol and progesterone on the regulation of their receptors in cultured bovine uterine epithelial and stromal cells was examined to determine the mechanisms involved in this process. Cells were obtained from cows at days 1-3 of the oestrous cycle and were cultured for 4 or 8 days in medium alone (RPMI medium + 5% (v/v) charcoal-dextran stripped newborn calf serum) or with oestradiol, progesterone or oestradiol and progesterone. At the end of culture, receptor binding was measured by saturation analysis. Specific binding of both [3H]ORG 2058 (16 alpha-ethyl-21-hydroxy-19-nor (6,7-3H) pregn-4-ene-3,20-dione) and [3H]oestradiol to epithelial and stromal cells showed high affinities (Kd = 1.1 x 10(-9) and 6 x 10(-10) mol l-1, respectively, for progesterone receptors; Kd = 5.5 x 10(-9) and 7 x 10(-10) mol l-1, respectively, for oestradiol receptors). In the stromal cells, oestradiol (0.1-10 nmol l-1) increased the number of oestradiol receptors from 0.21 +/- 0.06 to 0.70 +/- 0.058 fmol microgram-1 DNA and the number of progesterone receptors from 1.4 +/- 0.83 to 6.6 +/- 0.70 fmol microgram-1 DNA in a dose-dependent manner after 4 days of culture (P < 0.01). After culture for 8 days, the stimulatory effect of oestradiol increased. Progesterone (50 nmol l-1) had no effect on the number of oestradiol or progesterone receptors (P > 0.05). However, progesterone inhibited the stimulatory effect of oestradiol. In epithelial cells, the lower concentrations of oestradiol (0.1 and 1 nmol l-1) stimulated the number of progesterone receptors (P = 0.05) after 4 days culture, whereas the highest concentration of oestradiol (10 nmol l-1), progesterone (50 nmol l-1) and progesterone (50 nmol l-1) plus oestradiol (1 nmol l-1) had no effect. After culture for 8 days, the stimulatory effect of oestradiol decreased. In contrast to progesterone receptors, the number of oestradiol receptors increased with oestradiol concentration (P < 0.01). These data show that the number of progesterone receptors was higher in the stromal cells than in epithelial cells, whereas the number of oestradiol receptors was higher in the epithelial cells than in stromal cells. Oestradiol upregulates its own receptor and increases the number of progesterone receptors in both cell types in vitro, whereas progesterone has little effect, but inhibits the effects of oestradiol on progesterone receptors.

Rapid insulinotropic effect of 17beta-estradiol via a plasma membrane receptor

Impaired insulin secretion is a hallmark in both type I and type II diabetic individuals. Whereas type I (insulin-dependent diabetes mellitus) implies ss-cell destruction, type II (non-insulin dependent diabetes mellitus), responsible for 75% of diabetic syndromes, involves diminished glucose-dependent secretion of insulin from pancreatic beta-cells. Although a clear demonstration of a direct effect of 17beta-estradiol on the pancreatic ss-cell is lacking, an in vivo insulinotropic effect has been suggested. In this report we describe the effects of 17beta-estradiol in mouse pancreatic ss-cells. 17beta-Estradiol, at physiological concentrations, closes K(ATP) channels, which are also targets for antidiabetic sulfonylureas, in a rapid and reversible manner. Furthermore, in synergy with glucose, 17beta-estradiol depolarizes the plasma membrane, eliciting electrical activity and intracellular calcium signals, which in turn enhance insulin secretion. These effects occur through a receptor located at the plasma membrane, distinct from the classic cytosolic estrogen receptor. Specific competitive binding and localization of 17beta-estradiol receptors at the plasma membrane was demonstrated using confocal reflective microscopy and immunocytochemistry. Gaining deeper knowledge of the effect induced by 17beta-estradiol may be important in order to better understand the hormonal regulation of insulin secretion and for the treatment of NIDDM. receptor.

Environmental xenobiotics may disrupt normal endocrine function by interfering with the binding of physiological ligands to steroid receptors and binding proteins

The disruption of the reproductive system of male and female animals in the wild has been attributed to environmental chemicals (xenobiotics). The effects seen mirror alterations one might anticipate if the steroid hormone-dependent processes that regulate these systems were impaired. To determine whether xenobiotics (present at a concentration of 100 microM) exert their action through steroid-mediated pathways, we examined their ability to inhibit the binding of [3H]physiological ligands (present at a concentration of 7 nM) to the androgen and estrogen receptors, rat androgen-binding protein (ABP), and human sex hormone-binding globulin (hSHBG). The gamma- and delta-isomers of hexachlorocyclohexane, congeners of dichlorodiphenyl-trichloroethane (DDT; p,p'-DDT; p,p'-DDE; o,p'-DDT), dieldrin, atrazine, and pentachlorophenol, caused a statistically significant inhibition of specific binding of [3H]5 alpha-DHT to the androgen receptor that ranged from 100% (p,p'-DDE) to 25% (dieldrin). Methoxychlor, o,p'-DDT1, pentachlorophenol, and nonylphenol significantly reduced [3H]17 beta-estradiol binding to the estrogen receptor by 10, 60, 20, and 75%, respectively. The binding of [3H]5 alpha-DHT to ABP was inhibited 70% by the delta-isomer of hexachlorocyclohexane, but the gamma-isomer did not reduce binding significantly. Methoxychlor, p,p'-DDT, atrazine, and nonylphenol reduced [3H]5 alpha-DHT binding to ABP by approximately 40%. Nonylphenol reduced the binding of [3H]5 alpha-DHT to hSHBG by 70%. Hexachlorocyclohexane reduced [3H]5 alpha-DHT binding to hSHBG by 20%, but the stereospecific effects observed with ABP did not occur. o,p'-DDT and pentachlorophenol resulted in a statistically significant 20% inhibition of [3H]5 alpha-DHT binding to hSHBG. Some xenobiotics resulted in dissociation of [3H]ligands from their binding proteins that was statistically identical to that caused by the unlabeled natural ligand, whereas others resulted in slower or more rapid dissociation rates.

Regulation of oxytocin, oestradiol and progesterone receptor concentrations in different uterine regions by oestradiol, progesterone and oxytocin in ovariectomized ewes

The regulation of oxytocin, oestradiol and progesterone receptors in different uterine cell types was studied in ovariectomized ewes. Animals were pretreated with a progestogen sponge for 10 days followed by 2 days of high-dose oestradiol to simulate oestrus. They then received either low-dose oestradiol (Group E), low-dose oestradiol plus progesterone (Group P) or low-dose oestradiol, progesterone and oxytocin (via osmotic minipump; Group OT). Animals (three to six per time-point) were killed following ovariectomy (Group OVX), at oestrus (Group O) or following 8, 10, 12 or 14 days of E, P or OT treatment. In a final group, oxytocin was withdrawn on day 12 and ewes were killed on day 14 (Group OTW). Oxytocin receptor concentrations and localization in the endometrium and myometrium were measured by radioreceptor assay, in situ hybridization and autoradiography with the iodinated oxytocin receptor antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin. Oestradiol and progesterone receptors were localized by immunocytochemistry. Oxytocin receptors were present in the luminal epithelium and superficial glands of ovariectomized ewes. In Group O, endometrial oxytocin receptor concentrations were high (1346 +/- 379 fmol [3H]oxytocin bound mg protein-1) and receptors were also located in the deep glands and caruncular stroma in a pattern resembling that found at natural oestrus. Continuing low-dose oestradiol was unable to sustain high endometrial oxytocin receptor concentrations with values decreasing significantly to 140 +/- 20 fmol mg protein-1 (P < 0.01), localized to the luminal epithelium and caruncular stroma but not the glands. Progesterone treatment initially abolished all oxytocin receptors with none present on days 8 or 10. They reappeared in the luminal epithelium only between days 12 and 14 to give an overall concentration of 306 +/- 50 fmol mg protein-1. Oxytocin treatment caused a small increase in oxytocin receptor concentration in the luminal epithelium on days 8 and 10 (20 +/- 4 in Group P and 107 +/- 35 fmol mg protein-1 in Group OT, P < 0.01) but the rise on day 14 was not affected (267 +/- 82 in Group OT and 411 +/- 120 fmol mg protein-1 in Group OTW). In contrast, oestradiol treatment was able to sustain myometrial oxytocin receptors (635 +/- 277 fmol mg protein-1 in Group O and 255 +/- 36 in Group E) and there was no increase over time in Groups P, OT and OTW with values of 61 +/- 18, 88 +/- 53 and 114 +/- 76 fmol mg protein-1 respectively (combined values for days 8-14). Oestradiol receptor concentrations were high in all uterine regions in Group O. This pattern and concentration was maintained in Group E. In all progesterone-treated ewes, oestradiol receptor concentrations were lower in all regions at all time-points. The only time-related change occurred in the luminal epithelium in which oestradiol receptors were undetectable on day 8 but developed by day 10 of progesterone treatment. Progesterone receptors were present at moderate concentrations in the deep glands, caruncular stroma, deep stroma and myometrium in Group O. Oestradiol increased progesterone receptors in the luminal epithelium, superficial glands, deep stroma and myometrium. Progesterone caused the loss of its own receptor from the luminal epithelium and superficial glands and decreased its receptor concentration in the deep stroma and myometrium at all time-points. There was a time-related loss of progesterone receptors from the deep glands of progesterone-treated ewes between days 8 and 14. These results show differences in the regulation of receptors between uterine regions. In particular loss of the negative inhibition by progesterone on the oxytocin receptor by day 14 occurred only in the luminal epithelium, but is unlikely to be a direct effect of progesterone as no progesterone receptors were present on luminal epithelial cells between days 8 and 14.

Cyclosporin A potentiates estradiol-induced expression of the cathepsin D gene in MCF7 breast cancer cells

Although the physiological role of the immunophilins cyclophilin-40 and FKBP52 is unknown, their identification as components of the unactivated estrogen receptor has raised the possibility that they might influence receptor activity in response to the binding of immunosuppressants cyclosporin A and FK506, respectively. We have used Northern analysis to determine the influence of cyclosporin A on the expression of the estrogen-inducible cathepsin D gene in human MCF7 breast cancer cells. We report that 1-3 microM cyclosporin A can potentiate cathepsin D mRNA expression by up to 2-fold in cells treated with 10(-12) to 10(-10) M estradiol. A decreased potentiation effect was noted at higher hormone concentrations. Cyclosporin A alone was unable to induce cathepsin D expression and the increased gene activation observed with combined estradiol/cyclosporin A treatment was negated by the antiestrogen ICI 164,384. Our results suggest that the increased potency of estradiol in the presence of cyclosporin A is associated with an enhanced transcriptional activity of the estrogen receptor and support a role for receptor-associated cyclophilin-40 in the activation process.

[Effect of L-TYR on the uterine cytosol estradiol and progesterone receptors in rat]

The effect of L-TYR on rat uterine cytosol estradiol and progesterone receptor contents was studied. The rats were divided into 4 groups: proestrus, estrus, metestrus and diestrus. One horn of each uterus was injected with L-TYR (2 mmol/L, 0.1 ml), while the other with 0.1 ml 0.9% NaCl serving as control. The mole concentration of receptor was calculated with RRA and cytosol receptor content was expressed as fmol/mg protein. It was shown that L-TYR decreased significantly the uterine estradiol and progesterone receptors in proestrus, estrus and diestrus phases of the estrus cycle, but without effect on metestrus. This was most probably due to competitive combination of TYR with some functional groups of the estradiol receptor because of similar chemical conformation of TYR to estradiol. Threonine could also decrease, to some extent, the uterine cytosol progesterone receptor content at estrus and dioestrus phases. Serine had no effect on the contents of uterine cytosol either estradiol or progesterone receptor in normal and ovariectomized rats. The present observation indicates that L-TYR appears to affect the synthesis of the cytosol estradiol and progesterone receptor in the rat uterus independent, however, of endogenous ovarian sex hormones, since the effect is still present in the ovariectomized animals.

Pubertal benzpyrene exposition decreases durably the sexual activity of the adult male and female rats

Single benzpyrene treatment of 5 week old male and female rats significantly decreased their sexual activity at 3 months of age. Among the hormone preparations used nandrolone was comparatively practically ineffective, while estradiol decreased the lordosis quotient of females. In males benzpyrene produced a total failure of ejaculation. These results draw attention to the wide time-scale of receptorine and behavioral effects of the aromatic hydrocarbon, benzpyrene. These effects are detectable following fetal, neonatal or pubertal treatments, especially in females. In males, the negative effect was manifested after neonatal and pubertal treatments only. The experiments suggest that in some cases hormonal imprinting does not develop solely in the perinatal period but it might develop later.

[The effect of spermine on protein kinase activity and number of cytosolic estradiol receptors]

Spermine decreased distinctly the activity of Ca2+ -phospholipid-dependent protein kinases, whereas not affected the protein kinase A activity. Content of cytosol estradiol receptors was drastically decreased in rat uterine in presence of the polyamine. The data obtained and literature data suggest that activation of estradiol receptors appears to occur after phosphorylation by means of Ca2+ - dependent protein kinases, which are regulated via phosphoinositide-involving mechanism, i.e. these receptors acquire the ability to bind hormones.

Growth of LNCaP human prostate cancer cells is stimulated by estradiol via its own receptor

We report that growth of LNCaP human prostate cancer cells is significantly stimulated (up to 120% above control) by physiological estradiol (E2) concentrations. This growth increase appears to be comparable to that induced by either testosterone or dihydrotestosterone, as also reported by others. This paper presents novel illustrative evidence for estrogen-binding proteins and messenger RNA transcripts in LNCaP cells. In fact, 1) the reverse transcriptase-polymerase chain reaction system documented normal messenger RNA for estrogen receptors (ER); 2) the radioligand binding assay allowed the detection of high affinity, reduced capacity binding sites in both soluble and nuclear cell fractions; and 3) the immunocytochemical analysis showed a consistently intensive staining for both ER and progesterone receptors. Compared to other human estrogen-responsive mammary cancer cells, MCF7 and ZR75-1, ER expression in LNCaP cells was not significantly lower, as shown by levels of the ER transcripts, number of sites per cell, or femtomoles per mg DNA as well as the percentage and intensity of immunocytochemical staining. A relative estimate of ER expression obtained by matching LNCaP with another human prostate cancer cell line, PC3, always displayed significantly and consistently higher levels in LNCaP cells. The detection of relatively high type I ER content in either cell compartment of LNCaP cells was paralleled by a highly intensive staining for progesterone receptors. In addition, evidence that the synthetic androgen R1881 did not compete for type I binding of E2 and that any E2-induced growth was completely reversed by the pure antiestrogen ICI-182,780, but unaffected by the antiandrogen Casodex, clearly suggests that the biological response of LNCaP cells to E2 is mediated via its own receptor.

[Reductive effect of the sesquiterpenic lactone "Helenalin " and its metallic derivatives in the formation of the estradiol receptor complex in breast tumor tissue]

Chemotherapy for systemic therapy in breast cancer has been widely used, and has been supported by many varied compounds with different origins and different compositions. Nevertheless, all of them produce several side adverse effects which must be taken into account. For this reason we must study new possibilities in which the administered drug acts selectively on the tumour cell without injuring healthy tissue. For studying its effect, a gamma lactone called "Helenaline" and its metalic derivates He-Co, He-Hg and He-Cu were studied, which chemical composition allows them to react with -SH residues present in the tumour cell receptors, which when interspaced by a previous reaction, could modify its structural composition and finally its affinity by the hormone. The inhibition effect for formation of estradiol-receptor complex in breast tumour tissue using Helenaline 12 n M and 126 n M was studied, obtaining 14% and 56% inhibition effect respectively. When He-Co, He-Hg and He-Cu effect was studied, this effect was raised obtaining 11%, 10.5% and 60% with 12 nM and 44.5%, 74.4% and 86% with 126 nM respectively.

[Effects of gossypol acetate, danazol, progesterone and GnRH-A on estrogen and progesterone receptors of human endometrial cells]

In order to evaluate the drugs in treating endometriosis, the direct effects of gossypol acetate, danazol, progesterone, and gonadotropin releasing hormone-agonist (GnRH-A) on the isolated human endometrial cells were determined by DCC assay. The binding capacity of cytosolic estradiol receptor (E2R) and progesterone receptor (PR) in groups treated with gossypol acetate or progesterone decreased. In danazol-treated group, the binding capacity of PR decreased but not that of E2R. GnRH-A showed no significant effect on the binding capacity of E2R and PR. There was a significant linear correlation between the inhibitory rates of PR binding capacity of progesterone and danazol. The results suggested that gossypol acetate, danazol and progesterone might have peripheral effects mediated by steroid receptors, while GnRH-A work clinically through the central path way only.

Synthesis of A-ring fluorinated derivatives of (17 alpha,20E/Z)-[125I]iodovinylestradiols: effect on receptor binding and receptor-mediated target tissue uptake

We have prepared a series of 2- and 4-fluoro derivatives of the isomeric (17 alpha,20E)- and (17 alpha, 20Z)iodovinylestradiols (IVE2) and also the analogs substituted with either a 7 alpha-methyl (7 alpha-Me-IVE2) or 11 beta-methoxy group (11 beta-OMe-IVE2) and evaluated their in vitro and in vivo properties. Electrophilic substitution of the estrone derivatives with N-fluoropyridinium salt gave the 2- and 4-fluoro analogs which were subsequently converted to the 17 alpha-ethynyl derivatives. The tributylstannyl intermediates were obtained from the corresponding 17 alpha-ethynyl analogs using azobisisobutyronitrile or triethylborane as catalyst. All 12 products were also prepared as their no-carrier-added [125I]iodovinyl analogs via destannylation of the tributylstannyl precursors. Binding affinity for the estrogen receptor (ER) was in general higher for the 4-F derivatives as compared to the 2-F derivatives, while the 20Z isomers of the same compounds showed somewhat higher ER binding affinity as compared to the 20E isomers. The combination of an A-ring fluoro and 7 alpha- or 11 beta-substituent decreased ER binding affinity. Substitution of a fluoro atom at C-4 on either the 17 alpha-ethynylestradiol or isomeric 17 alpha-IVE2 enhanced the affinity of the parent molecule for the ER. A-ring fluorination of all other analogues tested had no effect or depressed ER binding affinity. Varying incubation conditions showed substantial differences in ER binding kinetics between the 20E and 20Z isomers. Tissue distribution in immature female rats showed that the highest uterus uptake and uterus to blood/nontarget ratios in the IVE2 series were obtained with the 4-F-(17 alpha,20Z)IVE2 isomer. The combination of A-ring fluoro and 7 alpha- or 11 beta-substitution decreased uterus uptake but had little or no effect on uterus to blood/nontarget ratios. The highest uterus to blood ratios were observed for the 4-F-(17 alpha,20E)11 beta-OMe-IVE2 (75 at 6 h and 125 at 12 h pi) reflecting rapid blood clearance and in vivo stability, as confirmed by the low levels of thyroid radioactivity. The lack of correlation between ER binding affinities and uterus uptake, and/or uptake ratios, suggests that other factors, including nonspecific binding and metabolic processes, also are involved in the tissue localization process. Our data suggest that 4-F substitution onto (17 alpha,20Z)IVE2 and (17 alpha,20E)11 beta-OMe-IVE2 enhances the potential of these compounds to function as SPECT imaging agents of ER-rich tissues.

Developmental changes in the gonadotropin releasing hormone neuron of the female rabbit: effects of tamoxifen citrate and pregnant mare serum gonadotropin

Developmental changes in immunostained gonadotropin releasing hormone neurons were demonstrated in female rabbits assigned to the following treatment groups: (i) tamoxifen citrate, 10 mg.kg-1 x day-1, in sesame seed oil (vehicle) (n = 24) or (ii) vehicle alone (control, n = 24) for 108 days; and (iii) 50 IU of pregnant mare serum gonadotropin on postnatal days 22 and 25 (n = 24) or vehicle on nontreatment days. Treatments had no effect on the total number of immunostained cells, but there was a significant (p = 0.0160) developmental shift from cells with smooth processes to rough. Group comparisons revealed that there was a significant (p < 0.001) age-related increase in the number of rough cells in pregnant mare serum treated rabbits between days 25 and 75, indicating an advancement in the shift from smooth to rough cells. Plasma gonadotropin levels, ovarian follicular development, and the developmental shift from smooth to rough cells were markedly suppressed by tamoxifen treatment compared with rabbits of the control group, while no difference in estradiol levels were found. Our results suggest that a developmental shift in gonadotropin releasing hormone cell morphology from smooth to rough precedes sexual maturity in the female rabbit.

Short term treatment of tamoxifen and estradiol on estradiol and progesterone receptors in rabbit uterus

Effects of tamoxifen (Tam) on cytosolic estradiol (E2) receptors (ERc), progesterone (P4) receptors (PRc), nuclear estradiol (ERn) and progesterone receptors (PRn) were studied in adult normal rabbit uterine tissue. The ratio of cytosol: nuclear estradiol receptors (ER) was greater in rabbits treated with Tam than E2 or control uterine tissues. Rabbit uterine progesterone receptors (PR) in E2 treated animal were greater than Tam-treated animals. Tam caused nuclear accumulation of estradiol receptor, and simultaneous administration of E2 + Tam 500, estradiol could not revert Tam mediated accumulation of ER. The results suggest that Tam has an essentially antagonist action in the rabbit uterine tissue.

[Anti-implantation action of nylestriol and its effect on uterine cytosol estrogen and progesterone receptor in rabbits]

The anti-implantation action of nylestriol in rabbit was studied. The changes of uterine cytosol estrogen and progesterone receptor (ER and PR) were analysed with the dextran-coated charcoal method. Plasma progesterone level of early pregnant rabbits was measured by radioimmunoassay. The results showed that oral nylestriol could obviously prevent the early pregnancy of rabbit by anti-implantation of blastocyst. The content of ER decreased in the nylestriol group (P < 0.01). The content of PR in nylestriol group was lower than that of the control group (P < 0.05). No significant difference of plasma progesterone level was noted between the control and treatment groups. These results suggest that there is close relationship between the anti-implantation effect of nylestriol and the decreased content of cytosol ER and PR during the pre-implantation period.

Effect of pesticides on oestradiol-receptor complex formation in rat uterus cytosol

The effect of gamma-1,2,3,4,5,6-hexachlorocyclohexane (lindane), 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2-methylthio-4,6-bis-isopropylamino-s-triazine (prometryne) on the formation of a specific oestradiol-receptor complex in the rat uterus cytosol has been examined in vitro and in vivo. Both in vitro and in vivo, the pesticides significantly (P < 0.001) inhibited the formation of the complex in the rat uterus cytosol. The decrease in the number of free specific binding sites on the receptors was determined. The affinity of binding was not modified under the influence of pesticides, and the Kd value was of the same order of magnitude (10(-9) M). The inhibition was found to be fully non-competitive.

3-Alkyl-2-phenylbenzo[b]thiophenes: nonsteroidal estrogen antagonists with mammary tumor inhibiting activity

A number of 2-(4-hydroxyphenyl)benzo[b]thiophenes with a hydroxy group in position 5 or 6 and a short alkyl group at C-3 were synthesized and studied for their estrogen receptor affinities. Relative binding affinities (RBA) for the calf uterine estrogen receptor ranged from 3 to 60 (17 beta-estradiol = 100). The highest RBA values were found with ethyl derivatives [3 (5-OH): 60; 7 (6-OH): 28]. In accord with their receptor affinity, all benzothiophenes exhibited endocrine activity in the immature mouse uterine weight test. At doses of 0.25-7.0 mg/kg body weight, they showed partial estrogen antagonism and usually weak estrogenic effects. All compounds entered tests with hormone-sensitive human MCF-7 breast cancer cells. At concentrations of 1 microM and higher, most of the derivatives displayed significant inhibition of cell growth. These results prompted us to test them in vivo for cytostatic activity using hormone-dependent MXT mouse mammary tumors. The 5-hydroxy derivatives 3 and 4 strongly inhibited the growth of these tumors. After 4 weeks of treatment with 3 x 4.2 mg/kg of compound 3, the average tumor weight was reduced by 83% vs control (tamoxifen at equimolar dose: 74%). The 6-hydroxy derivative 7 required higher doses (25 mg/kg) to give rise to the same antitumor effect. At the end of therapy, no increase of uterine weight due to an estrogenic effect was observed. We assume therefore that the antineoplastic activity of these compounds in this tumor model is due mainly to their estrogen antagonism.

[The content of sex steroid receptors and the activity of marker enzymes of estrogenic action in the uterus of androgen-sterile rats]

In rats with preserved ovaries, both in normal and in neonatally androgenized, the activity of enzymes kreatinphosphokinase and peroxidase cannot serve as the marker of the estradiol effect upon the uterus. In ovariectomised animals, the dynamics of activity of these enzymes corresponds to uterotropic responses to estradiol. but not to the dynamics of hormone receptor complexes. The data obtained makes doubtful the participation of the hormone receptor complexes in realisation of the estrogens effect upon the uterus.

Synthesis and biological evaluation of a series of gem-dichlorocyclopropanes as antitumor agents

As part of our continuous effort to produce non-steroidal antiestrogens demonstrating less intrinsic estrogenicity and greater antagonism than those in use, a series of Analog II (1,1-dichloro-2,3-diphenylcyclopropanes) derivatives was synthesized. The compounds were tested for their ability to inhibit the growth-stimulating action of estradiol in the immature mouse uterus and estrogen receptor (ER) (+) MCF-7 human breast cancer cells in vitro. Like Analog II, the derivatives were found to have no intrinsic estrogenicity (except 30) and they antagonized estradiol action less completely than the lead compound. Polarity improved the ER binding affinity of Analog II, but was quite small for all compounds, except 30, for which it was comparable to tamoxifen. Six compounds (8, 10, 14, 23, 29 and 30) demonstrated antiproliferative activity toward MCF-7 cells, in vitro, and the mean inhibition period over 6 days ranged from 20 to 37%. Only compound 30 was reversed by estradiol.

Effect of sho-saiko-to (TJ-9, Japanese herbal medicine) on estradiol receptors in the cytosol of hepatic sinusoidal endothelial cells

We first confirmed the presence of estradiol receptors in the cytosol of rat hepatic sinusoidal endothelial cells and then studied the effects of Sho-saiko-to (TJ-9) on the level of these cytosol estradiol receptors. As a result, we found that estradiol receptors are present in the cytosol of hepatic sinusoidal endothelial cells from rats. Moreover, when these cells were incubated with TJ-9, the level of cytosol estradiol receptors increased. These results suggested that TJ-9 acts on hepatic sinusoidal endothelial cells to increase the level of estradiol receptors, thereby affecting the immune reactions in the liver.

Decreased estradiol receptor concentrations in ethionine-induced fatty liver of rats

Ethionine, a methionine analogue, induces fatty liver in rats. The mechanism by which ethionine induces fatty liver is thought to be due to the inhibition of synthesis of very-low-density lipoprotein. Since the synthesis of lipoprotein is correlated with liver estradiol receptor concentrations, we examined the effect of ethionine on estradiol receptor concentrations in rat liver. Estradiol receptor concentrations in both cytosolic and nuclear fractions were greatly decreased by a single injection of ethionine at a dose of 0.5 mg/g body wt. In particular, the decrease in nuclear receptor concentrations was observed a few hours after the injection and correlated with the decrease in triglyceride content in the very-low-density lipoprotein fraction. These results suggest that liver estradiol receptor is involved in the pathogenesis of ethionine-induced fatty liver of rats.

Retinoic acid acts synergistically with 1,25-dihydroxyvitamin D3 or antioestrogen to inhibit T-47D human breast cancer cell proliferation

Although retinoic acid has been shown to inhibit proliferation in human breast cancer cells, the mechanisms by which these effects are mediated are not known. Since several steroid hormones and their synthetic antagonists also inhibit proliferation of human breast cancer cells, we investigated the interactions between retinoic acid, 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and antioestrogens in the control of human breast cancer cell proliferation in vitro. When T-47D cells, the most sensitive of six human breast cancer cell lines to the growth inhibitory effects of retinoic acid, were treated with retinoic acid and 1,25-(OH)2D3, a synergistic inhibitory effect on cell growth was observed. Retinoic acid also enhanced the growth inhibitory effect of various antioestrogens (4-hydroxytamoxifen, 4-hydroxyclomiphene or LY117018). However, retinoic acid did not affect oestradiol-induced growth stimulation. Measurement of the cellular receptors for 1,25-(OH)2D3 and oestrogen revealed no significant change in receptor levels following treatment with concentrations of retinoic acid which modulated growth. These results indicate that retinoic acid not only has direct growth inhibitory effects on breast cancer cell proliferation but also augments the effects of some other known regulators of breast cancer cell replication including 1,25-(OH)2D3 and antioestrogens. Synergism appears to involve interactions with steroid hormone action distinct from changes in steroid hormone receptor levels.

Modulation of proliferation, estradiol receptors and estrogen regulated protein PS2/BCEI in human breast cancer cell lines by gamma interferon

The effects of recombinant gamma interferon (IFN gamma) on proliferation, estrogen-receptor (ER) content, mRNA level and protein secretion of a breast cancer estrogen-induced protein pS2/BCEI were investigated in two human breast cancer cell lines, ZR75-1 and T47D. Both cell lines have estrogen and progesterone receptors and previously showed HLA class I and class II responses to IFN gamma (Int J Cancer 1990; 45: 1169). An antiproliferative effect of IFN gamma (1000-5000 U/ml) was observed in serum containing medium on ZR75-1 but not on T47D cells. Noninhibitory concentration of IFN gamma (100 U/ml) had sensitising antiproliferative effect with antiestrogens on ZR75-1 cells whereas IFN gamma did not modify the growth inhibition observed in T47D cells with antiestrogens. In serum-free, estradiol-free, phenol-red-free chemically defined medium (Cancer Res 1984; 44: 4553), IFN gamma abolished in ZR75-1 but not in T47D the 30% growth stimulation induced by estradiol. In ZR75-1 cells, IFN gamma induced a transitory 30-50% increase of ER content, as measured by ER-enzymoimmunoassay, at day 2 of culture, and reduced mRNA level and secretion of pS2/BCEI. In T47D cells, a 30-50% decrease of ER content was observed but only when cells were long term cultured (30 weeks) with IFN gamma. In this cell line, no transcription of pS2/BCEI was observed. Antiproliferative action of IFN gamma on ZR75-1 cells is associated with an inhibition of estradiol effects and a reduction of pS2/BCEI mRNA level and protein secretion.

Fibrocystic disease of the breast in premenopausal women: histohormonal correlation and response to luteinizing hormone releasing hormone analog treatment

Sixty-six patients with fibrocystic mastopathy were enrolled in the trial after being selected according to clinical, radioultrasonographic, and histologic criteria. No characteristic hormonal profile was noted in most patients (52%). Estrogen receptors or progesterone receptors, or both, were found in 57% of patients. Hormone receptor levels were correlated with atypical proliferative mastopathy (87.5%). Mastopathy was associated with a uterine fibroma or a fibromatous uterus in 73% of cases. All patients received intramuscular injections of a sustained delivery system (microcapsules) of luteinizing hormone releasing hormone agonist [D-Trp6]-LHRH, Ipsen-Biotech, Paris) for 3 to 6 months. In case of partial response at 3 months, an antiestrogen (tamoxifen, 40 mg/day, for estrogen receptor-predominant lesions) or a progestin (cyproterone acetate, 50 mg/day, for progesterone receptor-predominant lesions) was added to the luteinizing hormone releasing hormone agonist. A complete response was observed in more than half of the patients (n = 35, 53%) treated by [D-Trp6]-LHRH alone (n = 29) or associated with tamoxifen (n = 4) or cyproterone acetate (n = 2). A significant partial response was observed in 30 other patients (45%). Additionally, half of them received inhibitory drugs. The best responses were seen with cyst reformation (complete response, 100%) and fibrous block. Clinical responses to treatment with [D-Trp6]-LHRH alone were independent of hormone receptor status, but synergistic effects occurred with concomitant use of the corresponding inhibitory drugs. We conclude that chronic mastopathy, particularly when associated with uterine fibroma, can be successfully treated by luteinizing hormone releasing hormone analogs in premenopausal women.

[Effect of decapeptyl (D-TrpG GnPh) on estrogen receptors, progesterone receptors and tissue levels of estrogens (non-conjugated and sulfate-conjugated) in patients with uterine myoma]

Concentrations of estrogen receptors, progesterone receptors, unconjugated estrogens (estradiol and estrone) and sulfate-conjugated estrogens (estradiol sulfate and estrone sulfate) were determined in patients treated with Decapeptyl and in controls. After prolonged Decapeptyl therapy, a highly significant fall in progesterone receptors was evidenced; estrogen receptors were found to be decreased in the myoma as compared with the secretory phase in controls and in the myometrium as compared with the proliferative phase in controls. Tissue levels of estrone sulfate and estradiol sulfate decreased very substantially. In conclusion, Decapeptyl emerges as a very promising agent for the treatment of uterine myomas.

The effect of cortisol administration on hepatic and plasma estradiol-binding capacity in immature female rainbow trout (Oncorhynchus mykiss)

Implantation of a cortisol-containing pellet into the peritoneal cavity of immature female rainbow trout raised plasma cortisol levels within the range commonly observed in chronically stressed fish. In cortisol-implanted fish there was a significant decline in the concentration of hepatic estradiol-binding sites relative to sham-implanted controls. This consisted of a 35% drop in cytosolic binding sites and a 29% reduction in the number of nuclear estradiol-binding sites, by 4 weeks postimplantation. Plasma estradiol-binding capacity was also influenced by cortisol treatment. After 2 weeks there was a 33% increase in plasma estradiol-binding capacity of cortisol-implanted fish. Plasma estradiol levels were unaffected by cortisol implantation, suggesting that the effects of cortisol on estradiol-binding sites were not mediated by altering the rate of estradiol secretion. The results indicate a possible mechanism by which environmental stress may suppress vitellogenesis.

Aqua[1-(2,6-dichloro-4-hydroxyphenyl)-2- phenylethylenediamine](sulfato)platinum-(II) complexes with variable substituents in the 2-phenyl ring. 1. Synthesis and antitumor and estrogenic properties

Erythro- and threo-configurated aqua[1-(2,6-dichloro-4-hydroxyphenyl)-2- phenylethylenediamine](sulfato)platinum(II) complexes with variable substituents in the 2-phenyl ring (2-PtSO4 to 9-PtSO4: H, 4-F, 3-OH, 4-OH, 2,6-F2, 2,6-Cl2, 2-F/4-OH, 2-Cl/4-OH) were synthesized and tested for estrogenic and antitumor activities. The ligands were obtained by a three-step reaction. The stilbenes were reacted with a mixture of IN3 and NaN3 to yield the respective 1,2-diazido-1,2-diphenylethanes. The subsequent reduction with LiAlH4 led to the corresponding 1,2-diphenyl-ethylenediamines. The (sulfato)platinum(II) complexes were synthesized by reaction of Ag2SO4 with the diiodo complexes, which had been obtained by coordination of the diamines with K2PtI4. Two complexes, erythro-8-PtSO4 and erythro-9-PtSO4, possess antitumor and estrogenic effects and are therefore of interest for the therapy of breast cancer.

Estrogen-like effects of 7,12-dimethylbenz(a)anthracene on the female rat hypothalamo-pituitary axis

We have recently demonstrated that 7,12-dimethylbenz(a)anthracene (DMBA), a potent inducer of mammary tumors in rodents, can in vitro decrease the number of membrane dopamine D2 receptors and stimulate prolactin (PRL) release, by direct estrogen-like actions on anterior pituitary. In the present study, we tested the ability of DMBA to mimic the in vivo estradiol (17 beta E2) effects on pituitary D2 receptors and on PRL as well as LH release. We have found that DMBA, like 17 beta E2, when injected to ovariectomized rats, induced a decrease in the number of anterior pituitary D2 receptors, a release of PRL and exerted a biphasic (acute negative and longer term positive) action on LH secretion. We thus examined the ability of DMBA to interact with 17 beta E2 receptors in the hypothalamo-pituitary axis: DMBA binds to the pituitary cytosolic estrogen receptors with an affinity 0.001% that of 17 beta E2. Finally [3H]DMBA binds to hypothalamus-containing brain sections. This binding was displaced partially by RU 2858 a pure estrogen agonist and totally by tamoxifen, a purported estrogen antagonist. No competition for [3H]DMBA binding was observed with an androgen (RU 1881) or a glucocorticoid (RU 26988) agonist. From these data, it may be concluded that DMBA can act as a partial estrogen in pituitary and hypothalamic tissues.

Effect of ATP on the regulation of the steroid binding activity of the oestradiol receptor

We have observed that ATP induces a second type of oestradiol binding site with slightly lower affinity (Ka 3.3 x 10(8) M-1) and lower sedimentation coefficient (4 S) in cytosol from immature lamb uterus and MCF-7 cells. A factor isolated from immature lamb uterine nuclear extract was found to decrease the steroid binding activity of oestradiol receptor that had been purified by heparin Sepharose and oestradiol-Sepharose chromatography. Inhibition of this factor by known phosphatase inhibitors, indicated that this factor may be a phosphatase. Another factor isolated from immature lamb uterine cytosol was found to enhance the effect of ATP on receptor binding in cytosol from immature lamb uterus and MCF-7 cells. The ability of this factor to phosphorylate a partially purified cytosol receptor from immature lamb uterus when incubated with [gamma 32P]ATP, indicates that this factor is a phosphokinase. The phosphorylated products after labeling with [3H]tamoxifen aziridine were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Three phosphorylated proteins with molecular weights 150, 97, and 67 kDa bound [3H]tamoxifen aziridine. Ammonium sulphate precipitated cytosol oestradiol receptor from immature lamb uterus was inactivated with receptor inactivating factor and then reactivated with receptor activating factor in the presence of [gamma 32P]ATP and substantially affinity labelled with [3H]tamoxifen aziridine. The affinity labelled oestradiol receptor was immunopurified with the monoclonal antibody JS 34/32. Three proteins with molecular weights 67, 50 and 43 kDa specifically bound [3H]tamoxifen aziridine and only 43 kDa receptor fragment was phosphorylated. The relevance of inactivation/reactivation of oestradiol receptor to the dephosphorylation/phosphorylation of receptor is discussed.

Modulation of cytosolic sexual steroid receptors in autochthonous methylnitrosourea-induced rat mammary carcinoma following application of 2-chloroethylnitrosocarbamoyl-L-alanine linked to oestradiol or dihydrotestosterone

This study concentrated on the influence of 2-chloroethylnitrosocarbamoyl-L-alanine (CNC-L-ala) linked to oestradiol (CNA-L-ala-E2) or dihydrotestosterone (CNC-L-ala-DHT) in position 17 of the respective steroid hormone on tumour growth and receptor kinetics of methylnitrosourea-induced rat mammary carcinoma. Both compounds almost completely arrested logarithmically growing mammary carcinoma of Sprague-Dawley rats: in the first week CNC-L-ala-E2 blocked the growth of these tumours by 92% compared to untreated control animals while, in animals treated with the physically equimolar mixture of CNC-L-ala and oestradiol (positive control), tumour growth was inhibited by 51% only. CNC-L-ala-DHT arrested the tumour growth in the first week by 95%, while the respective positive control (CNC-L-ala plus dihydrotestosterone) effected a growth inhibition of 71% compared to the untreated control. These results correlate well with the influence of both drugs on the cytosolic receptor content of sexual steroid hormones in the tumours. CNC-L-ala-E2 depleted the content of oestradiol receptors and kept it down for a week, while concomitantly the content of progesterone receptors increased considerably and that of androgen receptors showed a short-lived decrease. CNC-L-ala-DHT depleted androgen receptors as well as progesterone receptors. The content of androgen receptors remained low for a week, while that of progesterone receptors recovered within 8 days. The content of oestrogen receptors showed a moderate decrease.

Subcellular distribution of cyclic adenosine 3',5'-monophosphate-binding protein and estrogen receptors in control pituitaries and estrogen-induced pituitary tumors

Binding of cyclic adenosine 3',5'-monophosphate (cAMP) and steroid receptors was studied in cytoplasmic and nuclear fractions of pituitaries from castrated rats, in rats subjected to acute (60 min) or short-term (4 days) estradiol (E2) treatment, and in diethylstilbestrol-induced pituitary tumors (DES-T). E2 receptors were primarily in nuclear extracts in all animals that were given estrogens, whereas cytosolic receptors were low to absent. Contrarily, castrated rats showed high quantities of cytoplasmic receptor but little in nuclear sites. The progestin receptor was induced only in 4-day E2-treated rats and in DES-T. cAMP binding was stimulated in cytosol from 4-day E2-treated rats and in DES-T, but a significant reduction in binding was also noted in nuclear extracts from DES-T. Scatchard analysis for the cytosolic cAMP-binding activity demonstrated a two-component system, and the increased cAMP binding obtained in DES-T seemed to be caused by an increase in the low-affinity, high-capacity binder [regulatory type II (RII) subunit of protein kinase]. Suggestion of the preferential estrogenic induction of RII was also obtained by DEAE-cellulose chromatography, which provided separation of RI and RII subunits. The results suggest that sustained estrogenization leads to induction of cytosolic cAMP-binding protein and increased levels of nuclear E2 receptor. In DES-T, this effect resulted in an inverse subcellular distribution of both binding proteins, which may be related to abnormal growth of the pituitary, as has been postulated for hormone-dependent mammary tumors.

[Effectiveness of hormonal therapy of endometrioid ovarian cysts]

Patients with ovarian endometriosis have been examined during the follicular and luteal phase of the ovulatory and the second phase of the anovulatory cycles. Estradiol and progesterone blood concentrations measured on operation days and during the respective ovulatory phases were in a normal range. Ovulation and endometrial hyperplasia reduced basal progesterone concentrations. Comparison of findings on steroid receptor systems in the endometrium and endometrioid ovarian cysts indicated that they were identical. The findings were different in ovulation and endometrial hyperplasia. These patterns provided criteria for endometrial response to female sex hormones by assaying endometrial intracellular steroid receptor systems in normally ovulating patients with ovarian endometriosis.

Glucocorticoids inhibit estradiol-mediated uterine growth: possible role of the uterine estradiol receptor

Stress-related activation of the hypothalamic-pituitary-adrenal axis (HPA) is associated with suppression of the reproductive axis. This effect has been explained by findings indicating that corticotropin-releasing hormone suppresses hypothalamic gonadotropin-releasing hormone (GnRH) secretion via an opioid peptide-mediated mechanism, and that glucocorticoids suppress both GnRH and gonadotropin secretion and inhibit testosterone and estradiol production by the testis and ovary, respectively. To evaluate whether glucocorticoids suppress the effects of estradiol on its target tissues, we examined the ability of dexamethasone to inhibit estradiol-stimulated uterine and thymic growth in ovariectomized rats. Estradiol alone, given daily for 5 days, caused dose-dependent uterine and thymic growth. Dexamethasone alone, given daily for 5 days, caused a dose-dependent decrease in body weight gain and in thymic growth. When estradiol and dexamethasone were administered simultaneously, however, body weight gain and thymic growth were also inhibited (p less than 0.05). Dexamethasone decreased estradiol-induced uterine cytosolic and nuclear estrogen receptor concentrations (E2 R0, p less than 0.05; E2nR0, respectively), but had no effect on estradiol-induced progesterone receptor concentrations (P4R0, p greater than 0.05). Levels of uterine glucocorticoid receptors were not affected by estrogen and/or dexamethasone treatment. These findings suggest that stress levels of glucocorticoids, administered over a 5-day interval, block the estradiol-stimulated growth of female sex hormone target tissues. This effect may be partially mediated by a glucocorticoid-induced decrease of the estradiol receptor concentration. Thus, another mechanism by which the HPA may influence reproductive function during stress is by a direct effect of glucocorticoids on the target tissues of sex steroids.

Effects of estradiol-17 beta and estriol on their binding sites in the rabbit uterus

1. Receptors for estradiol-17 beta (E2) and estriol (E3) were detected in the rabbit uterus. 2. Saturation analysis of estrogen binding sites in the cytosol showed that the dissociation constants of E2 and E3 for the high affinity binding sites were 1.8 +/- 0.5 nM and 2.3 +/- 0.3 nM, respectively, when dextran-coated charcoal was used to isolate free and bound ligands. 3. To eliminate non-specific (cross) bindings to their receptors, effects of unlabeled E2 and E3 on [3H]E3 and [3H]E2 bindings was examined. 4. [3H]E2 cytosol binding was observed to be specific for E2 and [3H]E3 cytosol binding was more specific for E3. 5. E2 priming to rabbits increased the binding sites for both E2 and E3, which was also more potent than E3 priming. 6. Moreover, the increase in E2 binding sites was greater than that in E3 binding sites. 7. These findings may suggest that there are separate binding sites for E2 and E3 in rabbit uterus and that synthesis of their binding sites is regulated by E2 but not E3.

Effects of chlordecone on progesterone receptors in immature and adult rats

The ability of the chlorinated pesticide chlordecone to induce the CNS (hypothalamus and preoptic area) plus pituitary and uterine progesterone receptors was examined in CDF-344 female rats following treatment with 25 micrograms estradiol or with 75 mg/kg chlordecone. In adult ovariectomized rats and in intact immature rats, estradiol increased progesterone receptors in neural and uterine tissues. This was in contrast to the effect of chlordecone. Chlordecone treatment of rats induced progesterone receptors in uterus of immature rats, but not in uterus of ovariectomized adult rats. In neither age group were CNS plus pituitary progesterone receptors increased following chlordecone treatment. These results suggest that the pesticide fails to mimic an estradiol-dependent event of substantial consequence to the CNS regulation of female reproductive functioning. These findings are discussed in terms of the possibility that chlordecone may, rather than mimicking, have the potential to attenuate estradiol's CNS effects. In addition to the effects of chlordecone on progesterone receptors, the effects of chlordecone in combination with estradiol were examined. Three temporal combinations between chlordecone and estradiol, which produce different effects on sexual behavior, were examined. The objective was to determine if chlordecone's inhibition of sexual behavior may have resulted from an attenuation of estradiol's production of CNS progesterone receptors. Chlordecone did not attenuate estradiol's elevation of CNS progesterone receptors under any of the three treatment conditions. Collectively, these studies demonstrate that chlordecone fails to mimic a well-defined and functionally significant effect of estradiol's interaction with the CNS estradiol receptor. However, they also suggest that the pesticide's inhibition of CNS estradiol events does not depend upon its attenuation of estradiol's induction of the CNS progesterone-receptor.

Heterogeneity of [3H]estradiol binding sites in the rat prostate: properties and distribution of type I and type II sites

In order to assess the rat prostate as a target tissue for receptor-mediated estrogen action, we have studied the properties and distributions of estrogen binding sites in the dorsolateral (DLP) and ventral (VP) prostate. Saturation analyses over a wide range of [3H]estradiol ([3H]E2) concentrations (0.5-100 nM) revealed two distinct types of binding sites in the cytosol and nuclear fractions of DLP of intact rats. The high affinity (type I) estrogen binding sites saturated at 2-4 nM of [3H]E2 and had a capacity of 170 fmol/mg DNA in the cytosol and 400 fmol/mg DNA in the nuclei. DLP type I sites had ligand specificity similar to that described for the classical estrogen receptors (ERs) found in female target tissues. The moderate affinity (type II) estrogen binding sites saturated at 15-30 nM of [3H]E2 and had a capacity of 850 fmol/mg DNA in the cytosol and 1600 fmol/mg DNA in the nuclei. DLP type II sites shared some characteristics of the type II ERs described for the rat uterus; they were estrogen specific, heat labile, and sensitive to reducing agents such as dithiothreitol. Saturation analyses on VP cytosols and nuclear fractions revealed only high affinity sites but no moderate affinity sites in the tissue preparations. Our finding that prostatic type II estrogen binding sites are present exclusively in the DLP supports the concept that basic biological differences exist between the two major prostatic lobes of the rat. Furthermore, our findings may help elucidate the observed differences in susceptibility between these two lobes to the hormonal induction of proliferative prostatic lesions.

Effect of triphenylacrylonitrile derivatives on estradiol-receptor binding and on human breast cancer cell growth

In a study of a series of 26 triphenylacrylonitrile derivatives (TPEs), we investigated the influence of several possibly interrelated factors on the proliferation of human breast cancer cell lines. (1) Chemical substituents: the test compounds were for the most part para-hydroxylated with increasingly bulky hydrophobic and/or basic side chains [isopropyloxy or (diethylamino)ethoxy] or standard reference compounds. (2) Relative binding affinities (RBAs): they competed diversely for [3H]estradiol (E2) binding to calf uterus cytosol and little, if at all, for binding to the [3H]tamoxifen-labeled antiestrogen binding site (AEBS) in lower speed supernatant. A multiparametric comparison of RBAs recorded for calf, rat, and mouse uterus cytosol estrogen receptor (ER) revealed a possible influence of species-specific receptor conformation and/or environment on binding. (3) Estrogen/antiestrogen potency: their stimulation and inhibition of the proliferation of the ER-positive human breast cancer cell line (MCF7) was measured. Compounds with only hydroxy substituents stimulated proliferation more markedly than methylated derivatives and had a maximum effect at 10(-11)-10(-6) M. Stimulation was related to the RBA for ER. Compounds with isopropyloxy or (diethylamino)ethoxy side chains only weakly stimulated MCF7 cell growth and more powerfully antagonized E2-promoted growth. The extent of inhibition depended upon the bulk of the side chain and could be reversed by 10(-7) M E2. Within the same concentration ranges, the test compounds were without effect on the BT20 ER-negative cell line. (4) Cytostatic and/or cytolytic activity: most compounds could arrest the proliferation of both MCF7 and BT20 cells at concentrations above 3 x 10(-6) M. This activity was thus independent of ER. Nevertheless, those compounds with a charged hydrophobic side chain, which were the most powerful antagonists of E2-promoted cell growth, were also the most cytotoxic. The overall results for all molecules on all parameters were submitted to a multivariate analysis (correspondence analysis) which revealed the progressive influence of increasing substitution by hydroxy and more bulky groups on the generation of antagonist activity and cytotoxicity.

Estradiol and chlordecone interactions with the estradiol receptor

The in vivo and in vitro effects of the chlorinated pesticide, chlordecone, on the estradiol receptor of adult ovariectomized CDF-344 rats were examined. Chlordecone's competition with [3H]estradiol for binding to the estradiol receptor in vitro was similar whether receptors were derived from neural or uterine tissue. In vivo, chlordecone led to nuclear retention of estradiol receptors in both tissues, but in comparison to estradiol, the latency for such retention was slower following chlordecone. Nevertheless, chlordecone- and estradiol-treated animals eventually achieved the same degree of nuclear retention in uterine tissue. In brain, estradiol-like levels of nuclear retention were never found in chlordecone-treated females. Estradiol receptor replenishment following chlordecone or estradiol was similar in uterine tissue but not in brain. Chlordecone's lesser ability to mimic estradiol's receptor dynamics in the brain may contribute to the apparent tissue differences in chlordecone's estrogenicity.