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Objective: To assess the expression of messenger RNA (mRNA) for estrogen receptors alpha and beta in the vaginal walls and uterosacral ligaments of premenopausal and postmenopausal women., Design: In vitro experiment., Setting: Academic research environment., Patient(s): Sixteen consecutively seen women who underwent hysterectomy., Intervention(s): Samples of anterior vaginal walls and uterosacral ligaments were obtained during hysterectomy., Main Outcome Measure(s): Reverse transcriptase-polymerase chain reaction analysis for estrogen receptor mRNA., Result(s): Messenger RNA transcripts for estrogen receptor alpha were present in all samples of vaginal walls (16/16) and uterosacral ligaments (16/16). Estrogen receptor beta mRNA was detected in all samples of vaginal walls from premenopausal women (12/12) but in none of those from postmenopausal women (0/4). Estrogen receptor beta mRNA was found in most samples of uterosacral ligaments from premenopausal women (10/12) and in some of those from postmenopausal women (2/4)., Conclusion(s): Estrogen receptors alpha and beta were expressed in the vaginal walls and uterosacral ligaments of premenopausal and postmenopausal women. Estrogen receptor beta was absent from the vaginal walls of postmenopausal women.

Studies on the mechanism of activation of estrogen receptor (ER) have led us to identify two classes of receptors. Effect of molybdate on the activation of ER was determined by their affinity for nuclei or DNA-cellulose. Molybdate caused inhibition of nuclear binding with rat uterine ER, but an increase in the binding was observed with rabbit uterine ER. Similar results were observed when DNA-cellulose was used instead of nuclei. To further test the diversity in ER activation, DNA-cellulose binding of ER from 10 primary breast cancer tissues was determined in the presence or absence of molybdate. ER from 8 tissues showed inhibition of binding, one showed an increase, and one was not affected by molybdate. These results indicate the presence of two classes of ER, one whose activation is inhibited by molybdate and another whose activation is either unaffected or stimulated by molybdate. Other differences between rat and rabbit uterine ER are also discussed.

The cytoplasmic estrogen receptor (ERc) and progesterone receptor (PRc) in mammary tumors have been recognized as useful biochemical markers for predicting the objective response of patients with advanced breast cancers to endocrine therapy. These proteins are also useful in the prognosis of gynecologic carcinoma. This report presents data showing the effect of sodium molybdate in the stabilization of estrogen and progesterone receptors. In rabbit uterine tissue, molybdate (20 mM) increased the binding of progesterone and estrogen to the receptors in several ways: (a) the apparent loss of detectable receptors during lengthy sucrose gradient analysis and at elevated temperature (30 degrees C) was reduced; (b) the instability of receptors due to storage at -70 degrees C was lessened, and (c) the conversion of the 7S PRc to the 3.5S form was minimized. Similarly, molybdate caused a qualitative and/or a statistically significant quantitative difference in receptor values for some human gynecologic tumors presented herein; the molybdate-associated changes vary with tumor specimen. Of the 8 tumors for which receptor values in the presence of molybdate (M+) and its absence (M-) can be compared, detectable ERc of 6 and PRc of 7 tumors increased with molybdate, and ERc of 2 and PRc of 1 tumor showed no change. In addition to the increase in receptor values, a concomitant shift of the 3-4S molecules to the 7-8S moieties was noted for some tumors (1 of 6 for ERc and 3 of 7 for PRc). In 2 receptor-poor tumor samples, ERc was only detected in M+ cytosols. These results show that molybdate is effective in reducing receptor degradation and stabilizes the 7-8S molecules from converting to 4S moieties. The addition of molybdate may be helpful for better quantitation of steroid receptors in clinical specimens.

The cytoplasmic content of estrogen and progesterone receptors (ERc and PRc) was measured in the rat uterine and mammary tissues during the period from late pregnancy through lactation. Uterine ERc and PRc, which sedimented at the 8S and 4S regions, respectively, of a 5-20% sucrose gradient, showed similar rise and decline patterns before and after parturition. Following a decline from the 15th day (114 +/- 13.7 fmol/mg protein) to the 20th day of pregnancy (57.7 +/- 10.2 fmol/mg protein), ERc levels increased almost 2.5-fold at the time of parturition. A decrease to the predelivery level by 24 h post-delivery was followed by a steady increase to 270.6 +/- 46 fmol/mg protein by 15 days of lactation. Uterine PRc levels also showed a peak similar to that of ERc at the time of parturition (24.3 +/- 1.1 fmol/mg protein). The level of ERc in mammary gland 6 h postpartum was the lowest (1.5 +/- 0.3 fmol/mg protein) and during the first 10 days of lactation ERc levels were maintained at about 10 fmol per mg of cytosol protein. Results herein suggest that levels of these steroid receptors may be hormonally regulated and that the uterus and mammary gland may have a different sensitivity to these regulatory control mechanisms. The physiological significance in the variation of these receptors in conjunction with the onset of parturition is discussed.

In an attempt to differentiate between the biochemical characteristics of hormonal-dependent and independent gynecologic tumors, monoclonal antibodies (mABs) MBr1 and MBr3 were used to detect tumor antigens. Steroid receptors and MBr1 and MBr3 determinants were assayed independently in a double-blinded manner. Of the 45 gynecologic tumors analyzed, 16 of 20 (80%) with both progesterone receptors (PR) (greater than 10 fm/mg protein) and estrogen receptors (ER) (greater than 5 fm/mg protein) also contained high levels of MBr1 determinant. However, these receptors were not quantitatively related to MBr1 activity. The 15 of 17 (88%) tumors that contained receptors below the discriminant levels also had low or undetectable levels of MBr1 activity. In tumors where only either PR or ER was present, 2 of 2 PR+/ER- tumors and 2 of 6 PR-/ER+ tumors expressed MBr1 antigen. No relationship of MBr3 antigenic activity to the receptors was established. These results show that MBr1-recognized antigen is expressed largely in steroid receptor-positive tumors and these data suggest that either the antigen itself or its carrier protein may be regulated by estrogen. Like steroid receptors, MBr1 antigens may have important prognostic value in gynecologic tumors.

From 1977 to 1981, 39 cases of primary cervical carcinoma were assayed for the presence or absence of cytoplasmic estrogen (ERc) and progesterone (PRc) receptors by a saturation point dextran-coated charcoal assay. The levels of ERc and PRc were compared with clinical stage, histologic type, histologic grade, menstrual status, age, and survival. Carcinomas were divided into positive and negative receptor groups with the use of greater than 5 fmol/mg of cytosol protein for ERc and 10 fmol/mg of cytosol protein for PRc as discrimination points. Survival of the patients studied was computed by means of the product-limit analysis according to Kaplan-Meier. A statistically significant difference in survival in the PRc + group versus the PRc - group in the total group of patients was noted with the Mantel-Cox test (P = 0.049). When patients were stratified according to menopausal status, a statistically significant difference in survival was noted between the PRc + group versus the PRc - group in the premenopausal patients only.

Cytosolic (ERc) and nuclear (ERn) estrogen receptors prepared from rat uteri were characterized by size-exclusion and ion-exchange HPLC. The oligomeric ERc eluted as a single, sharp peak near the exclusion volume of the gel column; ERn eluted as a broad peak. When salt-extracted ERn was partially purified sequentially by Sephadex G-200, DEAE-cellulose chromatography and polyacrylamide gel electrophoresis, the partially purified receptor moieties were not distinguishable by the sucrose gradient method, but showed characteristic retention times in the size-exclusion HPLC column. Further distinction in net surface charges was observed between ERc and ERn moieties by ion-exchange high-pressure liquid chromatography (HPLC). Molybdate-stabilized ERc was eluted as sharp peak at 0.27 M salt gradient. In contrast, fresh extracts of ERn emerged as a broad peak in the region of 0.1-0.2 M salt gradient. In the absence of molybdate, ERc dissociated into several 4-5 S molecules, which were well resolved in the DEAE column. This report, therefore, demonstrates the usefulness of size-exclusion and ion-exchange HPLC for steroid receptor analysis.

Tissue levels of cytosolic estrogen receptors (ERc) and progesterone receptors (PRc) have been shown to have prognostic meaning in hormonally responsive cancers arising in the breast and endometrium. Although carcinomas of the uterine cervix rarely respond to hormonal manipulation, the normal cervical stroma and epithelia contain ERc and PRc. To study the prognostic value of these receptors, 65 cervical carcinomas for ERc and PRc were assayed before initiation of surgical or radiation therapy. In premenopausal women, logistic models demonstrated that clinical stage, surgical stage, and receptor level independently predict survival. If confirmed in further studies, ERc and PRc may prove to be useful prognostic factors in the management of cervical carcinomas.

Forty-two cases of recurrent and 14 cases of advanced clinical stage (III and IV) endometrial carcinoma are presented, in which progesterone and estrogen receptors from the metastatic sites were measured. Mean survival time (time from recurrence or, in advanced stages, from the time of diagnosis to death or last follow-up), mean total survival time (time from diagnosis to death or last follow-up), and mean time to recurrence (time from diagnosis of primary tumor to the time of recurrence) were positively correlated with positive progesterone and estrogen receptor status and with histologic grade of tumor. No correlation was found with age, clinical stage, depth of myometrial invasion, or site of metastasis. However, when multiple variables were considered with the Cox regression model, the combination most highly correlated with survival included progesterone receptor, grade of tumor, and site of metastasis (pelvis vs. other sites). All differences were statistically significant (p less than 0.05). We conclude that measurement of progesterone and estrogen receptors in metastatic or recurrent endometrial tumors may be used as an additional prognostic variable.

This report describes the separation and characterization of estrogen receptors (ER) according to their degree of hydrophobicity and surface charges. Molybdate-stabilized [3H]ER from rabbit uterine cytosol was sequentially purified by passage through a size-exclusion pre-column, an anion-exchange column, and a hydrophobic interaction column. With fresh cytosol, a major radioactive peak was eluted from the DEAE columns; a major peak and a minor, less hydrophobic, peak were eluted from the hydrophobic column. In contrast, ER from frozen cytosol showed one peak in the DEAE-column and exhibited four radioactive peaks in the hydrophobic column. By sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis, [3H] tamoxifen aziridine(TA)-labelled ER showed radioactive bands at 62 and 48 kd. The subunits which were characterized by these radioactive bands were successfully separated by the hydrophobic column; the more hydrophobic subunit corresponded to the 62 kd band. The HPLC-purified [3H]TA-labelled ER subunits sediment at a 7.4-8.5S region in a low-salt sucrose gradient. These results show that differential negative surface charge and hydrophobic areas exist in the holo-receptor and its subunits, and the hydrophobic interaction HPLC column separates the two major 8S steroid binding subunits of ER.

A micro-fluorometric ELISA which required only 50 microliter of reagent in each step is reported here for rapid detection of anti-estrogen receptor (ER) antibody production by hybridoma cultures. In this study, several factors which influence the sensitivity of ELISA, e.g., incubation time, substrates, microtiter plates, concentration of coating antigens, choice and concentration of specific antibody and enzyme were evaluated. We observed that micro-fluorometric ELISA using 4-methylumbelliferyl phosphate-phosphatase system and MicroFluor W plates was the most sensitive; it detected readily 1 ng coating antigens or 1 ng antibody during a 15 min incubation. This system was used successfully for the detection of anti-ER antibodies in mouse immune sera, and in spent media from in vitro immunized spleen cells or hybridoma cells. This method is simple, sensitive, rapid and reliable for ER or anti-ER antibody determination.

Eighty-six cases of primary endometrial carcinoma were assayed for the presence or absence of cytoplasmic estrogen and progesterone receptors by the saturation point dextran-coated charcoal assay. The levels of cytoplasmic progesterone receptors and estrogen receptors were analyzed according to clinical stage, histologic type and grade of the tumor, presence or absence of lymph node metastases, myometrial invasion, and survival. The cases were divided into positive and negative receptor groups with levels chosen of greater than 10 fmol/mg of cytosol protein for progesterone receptor and 5 fmol/mg of cytosol protein for estrogen receptor as discrimination points. Statistically significant survival differences were found between estrogen receptor positive versus estrogen receptor negative patients, progesterone receptor positive versus progesterone receptor negative patients, and estrogen positive-progesterone receptor positive versus estrogen negative-progesterone receptor negative patients. Mean cytoplasmic estrogen and progesterone receptor levels were inversely proportional to grade. This report suggests that treatment protocols should be devised to reflect the prognostic significance of receptor status.

Interaction of estradiol receptor with chromatin was probed by nuclease digestion of receptor-chromatin complex. The complex was formed by incubating partially purified receptor with chromatin. Micrococcal nuclease digestion of the complex released a 7S form of receptor which could be converted to 2.8S form by DNAase I. Digestion of the complex with DNAase I yielded different forms of receptors ranging from 7S to 2.8S depending on the digestion time. Receptor distribution was also examined by isolating nuclei form tissue pre-incubated with radioactive estradiol. Micrococcal nuclease digestion of receptor-filled nuclei released 7S, 5.5S and 3.5S forms of receptors. Collectively, these results indicate that the 7S nuclear receptor may have an associated chromatin fragment which is sensitive to DNAase I activity. The desirable features of receptor-chromatin method over conventional methods for studies relating to receptor interaction at the gene site are discussed.

Twenty-five patients with measurable metastatic breast cancer and assays for estrogen receptor (ER) were studied. Of the 16 ER positive patients on anti-estrogen therapy, one had complete disappearance of all tumor for seven months and seven patients had more than 50% reduction in their measurable tumor for an average duration of 8.8 months. Seven other ER positive patients had stabilization of their tumors for an average interval of 8.4 months. Only one of the 16 ER positive patients progressed promptly. Conversely there was only one partial response in the nine ER negative patients and only two ER negative patients had stabilization of disease. Six out of nine ER negative patients progressed promptly. Correlation existed between the duration of response and absolute estrogen receptor level of the tumor. There may be a positive correlation between the response to antiestrogen therapy and response to endocrine ablation but prospective studies must be done to further define the role of antiestrogens in this regard.

This report presents the first application of ion-exchange high-performance liquid chromatography in the study of ER from the rabbit uterus. In the presence of sodium molybdate (20 mM), native ER was eluted as a sharp peak at 0.29 M NaCl by a linear salt gradient, but without molybdate, it resolved into 4 major peaks. Molybdate-stabilized ER from the DEAE column, similar to ER from crude cytosol, sedimented at the 6-8S region in low salt and 4S region in high salt linear sucrose gradients, and was excluded from size-exclusion HPLC. In contrast, dissociated ER subunits from DEAE eluates ranged from 3.5 to 4.5S, and showed differences in molecular weights in a size-exclusion column. These results show that the native ER is a large molecule which dissociates into smaller subunits in the absence of molybdate; each of the steroid-bound moieties differs in molecular weight and surface charge from the native molecule.