Characterization of the shed form of the human tumor-associated glycoprotein (TAG-72) from serous effusions of patients with different types of carcinomas.

Monoclonal antibody (MAb) B72.3 binds a high molecular weight tumor-associated glycoprotein designated TAG-72. This study reports the isolation and characterization of secreted TAG-72 directly from effusions of ovarian, colorectal, pancreatic, and endometrial carcinoma patients and compares them to TAG-72 derived from the LS-174T colon carcinoma xenograft. The B72.3-reactive antigen, TAG-72, was used as immunogen to produce second generation anti-TAG-72 MAbs. One of these second generation MAbs, CC49, had a higher affinity than that of B72.3 and was utilized as an affinity reagent in a procedure to purify the TAG-72 present in the serous effusions of carcinoma patients. A three-step purification procedure, utilizing heat extraction, CC49 antibody affinity chromatography, and gel filtration chromatography, resulted in 1000- to 4400-fold purifications of the TAG-72 derived from effusions, as analyzed using a double-determinant radioimmunoassay. Radiolabeled TAG-72 from each of the effusions demonstrated similar high molecular weight bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Similar results from the various effusions were also obtained in Western blotting analyses. Analyses of TAG-72 from the different effusions in radioimmunoassay using five different anti-TAG-72 MAbs revealed similar binding patterns. The results of these studies thus indicate that TAG-72 obtained directly from patients with ovarian, colorectal, endometrial, and pancreatic carcinomas and the LS-174T xenograft are highly similar in terms of immunochemical properties and antigenic profile.

Immunohistological distribution of the secretory endometrial protein, 'pregnancy-associated endometrial alpha 2-globulin', a glycosylated beta-lactoglobulin homologue, in the human fetus and adult employing monoclonal antibodies.

We have previously demonstrated that pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), the human glycosylated beta-lactoglobulin homologue (HG-BLG), is quantitatively the major secretory soluble protein product of the secretory endometrium during the latter half of the menstrual cycle and decidua spongiosa of the gestational endometrium during early pregnancy, and is principally localized to the glandular epithelium. In the present study employing monoclonal antibodies in immunohistological techniques, the distribution and localization has been examined in normal and pathological tissues of the adult and first-trimester fetus. No significant staining for alpha 2-PEG was detected in any nonreproduction-associated tissue in the normal adult nor any tissue in the fetus. In the adult, most intense staining was associated with the endometrial glandular epithelium in the uterus or in ectopic sites in patients with endometriosis. During the menstrual cycle and pregnancy, appearance of alpha 2-PEG in endometriosis was strongly linked with its appearance in uterine endometrial tissue, suggesting that endometriotic tissue exhibited competence to respond to the same hormonal milieu required to induce synthesis in the uterine endometrium. Localization to the mucosal epithelium of the Fallopian tube was consistent with synthesis of alpha 2-PEG, albeit at low levels, and staining at this site reflected fluctuations of staining within the uterus. Of the pathological specimens examined, staining was only detected in a proportion of ovarian carcinomas. No staining was detected in the mammary gland, a site of beta-lactoglobulin synthesis, whether obtained during pregnancy or lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor-like immunoreactivity in human endometrium.

Epidermal growth factor (EGF)-like immunoreactivity was detected in human endometrial tissues. The concentrations of the immunoreactivity fluctuated during the menstrual cycle. The highest levels were observed in the late proliferative phase with the concentrations being 0.50 +/- 0.06 ng/mg protein (M +/- SE, n = 5). Considering the presence of EGF receptors in human endometrium, EGF-like peptides may act in autocrine or paracrine fashions in human endometrium.

Value of immunohistochemical demonstration of several epithelial markers in hyperplastic and neoplastic endometrium.

The distribution of prekeratin, vimentin, epithelial membrane antigen (EMA), and secretory component (SC) was demonstrated immunohistochemically in 31 patients with adenomatous hyperplasia (AH), 12 patients with atypical adenomatous hyperplasia (AAH), and 39 patients with endometrial carcinoma. Prekeratin was presented in 94% of AHs, 92% of AAHs, and 87% of adenocarcinomas. Vimentin was detected in 68% of AHs, 50% of AAHs, and 37% of adenocarcinomas, showing decreased expression as the lesion progressed to malignancy (P less than 0.05). EMA was detected in 26% of AHs, 67% of AAHs, and 95% of adenocarcinomas (P less than 0.001). SC demonstrated focal and weak expression in 29% of AHs, but showed increased staining intensity in 67% of adenocarcinomas (P less than 0.01). Well-differentiated tumors expressed SC better than poorly differentiated tumors (P less than 0.01). All markers showed a heterogeneous staining pattern and, for a given histologic hyperplastic or neoplastic state, corresponded to several phenotypes. In conclusion, prekeratin seems to be a good marker for epithelial differentiation in hyperplastic endometrium, and EMA is a good marker in neoplastic endometrium. In hyperplastic lesions, the loss of vimentin expression in the absence of secretory changes gives rise to suspicions regarding their benign process. Also, EMA can help in distinguishing between hyperplastic and neoplastic states, while detection of SC may be of help in more precise grading of endometrial carcinoma.

Establishment of rat endometrial cell lines by retroviral mediated transfer of immortalizing and transforming oncogenes.

To study hormone responsive genes in differentiated epithelial cells and as a model for endometrial carcinoma, lines were established from primary rat endometrial cells by infection with replication-defective retroviruses carrying oncogenes and the selectable gene neo. The initial step involved immortalization through the large T antigen of SV40 to generate a line we designate RENT4, or with the E1a gene of adenovirus to generate lines referred to as RENE1 and RENE2. Additionally, lines generated by large T antigen of SV40 were superinfected with a replication-defective retrovirus harboring the v-Ha-ras oncogene and selected by the ability to form colonies in soft agar. The latter cell lines appeared fully transformed and were designated RENTR01 and RENTR03. Five established lines were characterized for steroid hormone receptors, alkaline phosphatase activity and their complement of the intermediate filaments vimentin and cytokeratin. With the exception of the RENE1 cells all other lines have normal levels of glucocorticoid receptor, whereas only RENE1, RENE2 and RENT4 were positive for the progesterone receptor. RENTR01, RENTR03 and, to a lesser extent, RENE1 exhibited differential expression of cytokeratins dependent upon whether the cells were grown on a substrata of NIH3T3 cells. When grown on formalin-fixed NIH3T3 cells, RENTR01 and RENTR03 cells appeared to differentiate or rearrange themselves in culture. Individual islands of cells showed a heterogeneous pattern of intermediate filaments with vimentin-positive cells localized to the outer portion of the islands whereas cytokeratin-positive cells are seen on the insides of these structures.

Two-dimensional polyacrylamide gel electrophoresis of proteins synthesized and released by conceptuses and endometria from pony mares.

Conceptuses were obtained from pony mares on each day of pregnancy between Days 12 and 28, and on Days 39, 45, 65 and 100. Endometrium was obtained from mares at Days 12, 14, 16, 18, 39, 45, 65 and 100 of pregnancy, and from non-pregnant mares during anoestrus, during transition into the breeding season, at oestrus, or during dioestrus. Tissues were incubated in vitro for 24 h with L-[3H]leucine. Proteins synthesized and released into the culture medium were analysed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and fluorography. Conceptuses obtained before Day 14 after ovulation released a characteristic pattern of labelled proteins. These included two groups of apparent isoelectric variants of relative molecular weights (Mr) 30,000-40,000 (pI values 4.5-5.5 and 6-7), one group of Mr approximately 22,000 (pI 6.5-7), and large protein(s) that did not enter the 10% polyacrylamide gel. After Day 14 the array of labelled proteins had changed and resembled that produced by isolated yolk sac at the later stages of pregnancy studied. Included amongst these were several acidic polypeptides with Mr 20,000 (pI 5-6). The endometrial samples released an array of non-dialysable polypeptides into the culture medium. Fluorograms could be assigned to one of three general groups, with endometrium from mares within each group producing similar patterns of labelled proteins. The first group consisted of anoestrous, transitional and ovariectomized mares, and mares at oestrus or Day 1 or Day 18 after ovulation. The second group was comprised of mares at Days 12-16 of dioestrus or Days 12-18 of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for steroid control of a putative angiogenic factor in the porcine uterus.

The formation of new capillaries, both in extraembryonic membranes and in the maternal endometrium, is an essential prerequisite for appropriate feto-maternal relationships throughout pregnancy. At present there is no indication of the nature of the uterine angiogenic stimulus. In-vitro, degradation products of hyaluronic acid, following its catalysis by hyaluronidase, have been shown to have angiogenic properties. In the current study, levels of hyaluronic acid in endometrial tissues and of hyaluronidase and hyaluronic acid in uterine flushings were measured during the oestrous cycle and early pregnancy. The concentration of both hyaluronic acid and hyaluronidase in uterine flushings followed the growth and regression of the corpus luteum, in that basal levels detected on days 0 and 6 increased to peak concentrations on days 12 and 15. By day 18, levels of both hyaluronidase and hyaluronic acid had decreased in cyclic gilts, but remained increased in pregnant pigs. Tissue concentrations of hyaluronic acid were not affected by pregnancy or by the day of the oestrous cycle. In a subsequent experiment, four groups of gilts were ovariectomized on day 4 and thereafter received daily injections of corn oil, progesterone, oestrogen or a combination of oestrogen and progesterone. Hyaluronidase was undetectable in uterine flushings collected on day 15 from corn oil- and oestrogen-treated gilts, but present in similar amounts in uterine flushings from gilts treated with progesterone and progesterone plus oestrogen. Similarly, uterine fluid concentrations of hyaluronic acid were increased in progesterone- and progesterone plus oestrogen-treated gilts, but not in corn oil- or oestrogen-treated pigs. Tissue concentrations of hyaluronic acid were unaffected by steroid treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Human 'pregnancy-associated endometrial alpha 1-globulin', a 32 kDa insulin-like growth factor-binding protein: immunohistological distribution and localization in the adult and fetus.

We have previously shown that pregnancy-associated alpha 1-globulin, a small molecular weight (32 kDa) insulin-like growth factor-binding protein (IGF-BP), is quantitatively the major secretory protein product of the decidualized endometrium during human pregnancy and is localized principally in the decidual cell. In the present study, employing monoclonal antibodies in immunohistological techniques, the distribution and localization of IGF-BP has been examined in normal and pathological tissues of the adult and first trimester fetus. In the adult, most intense reactivity was associated with endometrial stroma and their derived decidual cells in the uterus or in ectopic sites in patients with endometriosis. During the menstrual cycle, the appearance of IGF-BP in endometriotic tissue was linked with its appearance in uterine endometrial tissue. The only other adult cells where significant staining was detected was in the luteal cells of the corpus luteum. Production of the protein was not a feature of carcinomas. In the fetus, the protein was localized in lymphoid-myeloid progenitor cells and hepatocytes of the liver and at lower levels in testicular Leydig cells and adenocortical cells. These observations suggest highly specific tissue expression of this protein and support a specialized role for this protein in progenitor cells of the lymphomyeloid system, in certain steroid hormone-producing cells and in the decidual cell in pregnancy.

Suppression of lymphocyte reactivity by culture supernatant from horse embryos and endometrium.

The mechanisms that permit maternal tolerance of the conceptus allograft during early pregnancy in the mare have not been investigated. Embryos and endometria were collected from mares 14 days after ovulation and cultured for 20.5 h. The effect of addition of culture supernatant on incorporation of [3H]thymidine by equine peripheral blood lymphocytes was studied. Culture supernatant from endometrium of nonpregnant mares did not affect lymphocyte blastogenesis, but supernatant from both embryos and endometrium of pregnant mares reduced concanavalin A (Con A)- and phytohemagglutinin-induced blastogenesis. Five of six cultures performed in the present of indomethacin did not contain immunosuppressive factors. The suppressive effect on Con A-induced blastogenesis was eliminated by charcoal treatment of the supernatants and reduced by treatment with trypsin or heat. Blastogenesis of bovine lymphocytes was inhibited by culture supernatant of endometrium from pregnant mares, but not by embryo supernatant. Preincubation of blood lymphocytes with supernatants from endometrium of pregnant mares enhanced subsequent incorporation of [3H]thymidine by lymphocytes. A 24-h delay in addition of embryo culture supernatants significantly reduced the degree of immunosuppression. These results suggest that probably more than one substance interacts with the lymphocyte cultures and the observed blastogenesis reflects the end result of the interaction between suppressive and stimulating factors. The lymphocyte inhibitory effect evident in supernatants from embryos and endometrium from pregnant mares may be important in local immunosuppression and maternal acceptance of pregnancy.

Endometrial concentrations of ampicillin in mares after intrauterine infusion of the drug.

Serum concentration of ampicillin, a semisynthetic penicillin, was measured in mares at various time intervals up to 24 hours after intrauterine infusion of 3 g of ampicillin. Blood samples were drawn immediately before infusion and at 1-, 4-, 10- and 24-hour intervals after infusion. At postinfusion hour 24, two endometrial biopsy specimens were obtained to measure endometrial concentrations of ampicillin. Blood was drawn twice as part of the 24-hour postinfusion sample collection, once before removal of the biopsy specimens and again 5 minutes after removal of the biopsy specimens. After drug infusion, more diestrous mares had detectable serum ampicillin concentration than did estrous mares for all samples, except the 24-hour prebiopsy sample. None of the 24-hour prebiopsy serum samples had detectable ampicillin concentration, but ampicillin was detected in the serum of 4 of 5 diestrous mares after endometrial biopsy. Endometrial concentrations of ampicillin were detectable at postinfusion hour 24 in estrous and diestrous mares, but were not different. All 24-hour biopsy specimens had ampicillin concentrations greater than the ampicillin minimal inhibitory concentration.

[The dependence of estradiol and progesterone reception in the endometrium on its histological structure in women with the syndrome of luteal phase failure]. / Zavisimost' retseptsii éstradiola i progesterona v éndometrii ot ego gistostruktury u zhenshchin s sindromom nedostatochnosti liuteinovoi fazy tsikla.

A study of the level of the sex steroid receptors in the endometrium of women with the syndrome of insufficiency of the luteal phase of the cycle (ILP-syndrome) has shown that disorders of receptor processes affect, first of all, progesterone receptors. An increase in a degree of a delay of endometrial development was accompanied by a rise of the level of progesterone in the endometrium which depended on the estradiol-progesterone ratio in the circulation, detectable on the 20th day of the menstrual cycle. The ILP-syndrome is characterized by the sufficient induction of progesterone receptors at the end of the proliferative--the beginning of the luteal phase of the cycle and by their insufficient inhibition with a low level of progesterone in the middle of the luteal phase. Insufficient synthesis of receptors as a result of sharp hypoestrogenemia is less frequent. The primary affection of the receptor apparatus as a cause of the ILP-syndrome against a normal hormonal background in the examinees was undetectable.

Local alteration in adenylate cyclase activity and stimulation response at implantation site in rabbit endometrium during early pregnancy.

Adenylate cyclase activity and its hormonal stimulation were measured in endometrial tissue, and sex steroid levels were quantified in uterine tissue collected from pregnant and estrous rabbits. The tissues from pregnant animals were separated into implantation (ES) and interimplantation (IES) sites. Adenylate cyclase activity was measured in broken cell preparations by enzymatic conversion of alpha-32P-adenosine triphosphate (ATP) into 32P-cyclic adenosine 3', 5'-monophosphate using Mg2(+)-ATP as a substrate. The activity was measured with no addition (basal) and after stimulation with guanosine triphosphate (GTP), NaF, or increasing doses (1 nM to 100 microM) of isoproterenol (ISO) and prostaglandin E2 (PGE2). The presence of GTP was necessary to observe a stimulation by ISO and PGE2. During pregnancy, adenylate cyclase activity was reduced compared to activity at estrus on Day 6.5 (IES and ES) and on Day 9 (IES); however, it reached its highest level at ES (Day 9). The regulation of isoproterenol response followed a similar pattern. Dose responses to PGE2 were markedly affected by physiological status. The response was higher during pregnancy than at estrus, and response (percent of GTP), as well as sensitivity, was higher in IES than in ES on Day 6.5 and even greater on Day 9. The levels of estradiol (E2) were reduced during pregnancy, but comparable in ES and IES; however, progesterone (P) levels were reduced in ES, and the E2/P ratio was significantly higher (p less than 0.01) in ES (15 +/- 1, 17 +/- 2) than in IES (8 +/- 1, 6 +/- 0.8) on Days 6.5 and 9, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical study of a rat membrane protein which induces a selective potassium permeation: its localization in the apical membrane portion of epithelial cells.

We previously reported a novel rat membrane protein that exhibits a voltage-dependent potassium channel activity on the basis of molecular cloning combined with an electrophysiological assay. This protein, termed IsK protein, is small and different from the conventional potassium channel proteins but induces selective permeation of potassium ions on its expression in Xenopus oocytes. In this investigation, we examined cellular localization of rat IsK protein by preparing three different types of antibody that specifically reacts with a distinct part of rat IsK protein. Immunohistochemical analysis using these antibody preparations demonstrated that rat IsK protein is confined to the apical membrane portion of epithelial cells in the proximal tubule of the kidney, the submandibular duct and the uterine endometrium. The observed tissue distribution of rat IsK protein was consistent with that of the IsK protein mRNA determined by blot hybridization analysis. In epithelial cells, the sodium, potassium-ATPase pump in the basolateral membrane generates a sodium gradient across the epithelial cell and allows sodium ions to enter the cell through the apical membrane. Thus, taking into account the cellular localization of the IsK protein, together with its electrophysiological properties, we discussed a possible function of the IsK protein, namely that this protein is involved in potassium permeation in the apical membrane of epithelial cells through the depolarizing effect of sodium entry.

Tumor markers of epithelial ovarian neoplasms.

Ninety-three formalin-fixed, paraffin-embedded surgical specimens from 69 ovarian tumors representing all five epithelial cell types were studied by immunohistochemistry, peanut and ulex lectin binding, and carbohydrate histochemistry. Carcinoembryonic antigen (CEA) was mostly noticeable in mucinous tumors (21 of 26). Glycogen was highly prevalent in clear cell (8 of 9) and endometrioid (4 of 6) carcinomas, in contrast to serous carcinomas (3 of 6), where it was only focally distributed, and was completely absent in all mucinous tumors. Among the different types of malignant tumors examined, mucinous carcinomas most frequently contained neutral mucins (6 of 8). In mucinous tumors, an increase in CEA content and a decrease in the total mucin secretion, particularly the strongly acidic sulfated group, were found to parallel the increased malignant potential of the tumor. Peanut and/or ulex lectin binding was a feature common to almost all epithelial neoplasms. Although peanut lectin showed a slightly higher affinity to serous and clear cell tumors, while ulex lectin was bound more to mucinous and endometrioid neoplasms, distribution of D-galactose and L-fucose does not have a diagnostic utility in these tumors. Placental lactogen was detected in 3 of 17 benign tumors and one of 19 tumors of low malignant potential (LMP). The beta subunit of hCG was found in one of 17 benign tumors, in 2 of 19 LMP tumors, and in 3 of 31 carcinomas.

Estrogen and progestin receptors in the reproductive tract of male and female primates.

With the aid of monoclonal antibodies specific to the estrogen and progestin receptors, we have examined the cellular localization of these proteins in the reproductive tract of male and female macaques. Two striking findings have resulted from our work with these new reagents. First, these receptors are detectable only in cell nuclei, regardless of hormonal treatment, and second, they are often detectable in stromal, but not epithelial cells when the epithelial cells undergo various estrogen or progestin-dependent events. The latter observation has led us to conclude that stromal cell-epithelial cell interactions may play previously unappreciated roles in the hormonal control of the primate reproductive tract. The lines of evidence that have drawn us to this conclusion will be reviewed.

[The cellular localization of the fertility alpha 2-microglobulin in tumors of the reproductive system]. / Kletochnaia lokalizatsiia al'fa-2-mikroglobulina fertil'nosti v opukholiakh reproduktivnoi sistemy.

Seventy-five samples of human tumors were examined immunohistochemically for fertility alpha-2-microglobulin also known as progesterone-associated protein of the endometrium. The protein was detected in 35.7% (5 of 14) endometrial cancer samples and in 20% (2 of 10) of ovarian malignancies. Tumors of the stomach, colon, breast, lung and some other sites failed to reveal the antigen with the exception of a single case of pulmonary adenocarcinoma which showed the ectopic expression of the protein. Fertility alpha-2-microglobulin is stage-specific tissue marker of the endometrium. It is expressed at the final stage of cell differentiation and is partially lost in cancer.

MSN-1 antibody in the evaluation of female genital tract adenocarcinomas.

The reactivity of a new monoclonal antibody (MAb), MSN-1, raised against a human endometrial cancer cell line (SNG-II), was studied in a variety of endometrial, endocervical, and ovarian carcinomas as well as normal cycling endometrium. Moderate to strong reactivity (2-3+) was seen in six of nine normal secretory endometria (67%), one of 10 normal proliferative endometria (10%), 18 of 18 endometrial adenocarcinomas (100%), 10 of 11 endometrioid ovarian adenocarcinomas (91%), seven of nine clear cell ovarian adenocarcinomas (78%), one of 12 endometrial hyperplasias without atypia (9%), two of four endometrial hyperplasias with atypia (50%), zero of five endometrial serous adenocarcinomas, two of 17 serous ovarian adenocarcinomas (12%), zero of 10 intestinal-type mucinous ovarian adenocarcinomas, and zero of nine metastatic adenocarcinomas in ovary. Endocervical adenocarcinomas showed moderate to strong staining in 75% (six of eight). It is concluded that MSN-1 can be used to confirm endometrioid/clear cell differentiation in ovarian and endometrial tumors, cannot be used to discriminate endocervical from endometrial differentiation, cannot be used to discriminate atypical hyperplasia from carcinoma, and may be useful to distinguish between atypical (premalignant) endometrial hyperplasias and those without atypia.

Diameter increase of collagen fibrils of the mouse endometrium during decidualization.

The diameter of collagen fibrils was measured in different regions of the antimesometrial endometrium of mice on days 5, 6, and 7 of pregnancy as well as in the endometrium of virgin mice. The average diameter of fibrils of virgin mice was 39.18 nm (range: 20-80). In the region of fully decidualized cells, the averages and ranges were 45.32 nm (30-170), 89.39 nm (30-270), and 125.88 nm (20-370), respectively, on days 5, 6, and 7 of pregnancy. Thick fibrils larger than 70 nm had irregular profiles. Our results show that the increase in diameter is associated with the decidualization of the mouse endometrium.

S-100 protein in glands within decidua and cervical glands during early pregnancy.

Strong immunoreactivity with polyclonal S-100 protein antisera and monoclonal S-100 alpha subunit antiserum was found in glandular cells of the decidua basalis and cervical polyps during early pregnancy. Immunoreactive S-100 protein was negative in glandular cells of the endometrium and cervix of nonpregnant women. It was also negative in endometrial hyperplasia and endometrial carcinoma. While the function of S-100 protein is not known, a relationship between humoral factors related to pregnancy and expression of S-100 protein gene is suggested by the results of this study.

Peri-implantation phase endometrial estrogen and progesterone receptors: effect of ovulation induction with clomiphene citrate.

The effects of clomiphene citrate on endometrial nuclear estradiol receptors and progesterone receptors were examined in 10 normal women during an untreated cycle (control) and during treatment with 50 mg clomiphene citrate and 150 mg clomiphene citrate daily on days 5 through 9. Concentrations and binding constants of the receptors were determined in endometrium obtained 8 to 12 days after midcycle luteinizing hormone surge. Scatchard plots for both estrogen receptors and progesterone receptors were linear, indicating only one type of high-affinity binding sites. In control cycles, estrogen receptor levels (mean +/- SEM) were 199.6 +/- 23.1 fmol/mg deoxyribonucleic acid, (n = 8) and were not significantly different from either 50 mg clomiphene citrate (180.5 +/- 19.1 fmol/mg deoxyribonucleic acid, n = 6) or 150 mg clomiphene citrate (194.3 +/- 35.2 fmol/mg deoxyribonucleic acid, n = 4). Similarly, the dissociation constants were unaffected by clomiphene citrate treatment. The concentrations of progesterone receptors in the control cycles (613 +/- 31 fmol/mg deoxyribonucleic acid, n = 5) and treatment cycles (50 mg clomiphene citrate -652.8 +/- 121 fmol/mg deoxyribonucleic acid, n = 6; 150 mg clomiphene citrate -592.6 +/- 31 fmol/mg deoxyribonucleic acid, n = 7) were also not significantly different. Clomiphene citrate also did not affect dissociation constants for progesterone receptors. Therefore, ovulation induction with clomiphene citrate apparently did not affect peri-implantation phase endometrial estrogen receptors and progesterone receptors or their respective binding constants.