Isolation of a keto sugar specific agglutinin from rat uterus

A ketosugar-specific agglutinin has been identified and purified to apparent homogeneity by affinity chromatography from the three days post-coital rat uterus. This protein is not found in other stages of estrous cycle. The agglutinin is glycoprotein, moves as single band with molecular weight 37,000 in polyacrylamide gel electrophoresis and pI is 4.2. Among the ketosugars, fructose and ribulose effectively inhibit the agglutinin activity, beside these sugars, mannose, glucose, alpha methyl-mannoside and glucoside are also effective as potent inhibitors. Possible roles of this protein in pregnancy are discussed.

Two-dimensional gel electrophoresis of endometrial protein in human uterine fluids: qualitative and quantitative analysis

By combining two-dimensional gel electrophoresis, protein staining and a sensitive computer-assisted gel scanning system, it was possible to examine human uterine fluid (n = 56) qualitatively and quantitatively for the presence of endometrial proteins. The protein concentration of uterine fluids ranged from 0.1 to 12.0 mg/ml with early secretory phase samples (n = 15) having significantly less protein (0.72 +/- 0.2 SEM mg/ml p less than or equal to 0.05) than the proliferative phase (n = 57) samples (1.58 +/- .29 SEM mg/ml). Whole blood contamination of uterine fluid, as measured by hemoglobin content, averaged 6.2 +/- 0.88% throughout the menstrual cycle. Human uterine fluids collected throughout the menstrual cycle were found to contain serum and up to 24 other proteins in addition to those previously described (MacLaughlin and Richardson, 1983). These proteins represent approximately 1% of the total protein in the gels and exhibit isoelectric points from 4.5 to 7.0 and molecular weights in the 26,000 to 60,000 range. These proteins are absent from human serum, which exhibits an identical pattern whether obtained in the proliferative or secretory phase of the menstrual cycle. These secreted endometrial proteins now become the standard against which to compare proteins identified in vitro using organ, gland and cell culture techniques and to characterize proteins that are regulated by steroid hormones in vivo.

Temporal and receptor correlates of the estrogen response in sheep

Uterine blood flow and uterine cytosol and nuclear estrogen receptors were measured at critical times during estradiol-induced vasodilatation in acute anesthetized and chronic conscious sheep preparations at estradiol bolus injection frequencies from 1 to 24 hours. During acute experiments, the uterine blood flow response was muted and cytosol estrogen receptor replenishment did not occur whereas full replenishment occurred in 12 hours in conscious ewes. In ewes treated with daily estradiol that had a stable daily uterine blood flow response, the uterine blood flow response 24 hours after uterine biopsy was similar to the preoperative one. Analysis of the duration of peak uterine blood flow levels and the rate of uterine blood flow descent from peak levels showed that an interval of 18 hours between estradiol injections was necessary for the uterine blood flow response to approximate that observed after 24 hours. These observations suggest: (1) that uterine vascular receptor replenishment is delayed compared with that of the total uterus; (2) that operative stress compromises cytosol estrogen receptor metabolism and possibly nuclear estrogen receptor function; (3) that the delayed maximum uterine blood flow response to estradiol in ewes previously untreated with estradiol is due to a trophic uterine effect of daily estradiol stimulation.

Distribution of trimethoprim and sulfametopyrazine in the female reproductive tract

A combination of trimethoprim (TMP) 250 mg and sulfametopyrazine (SMP) 200 mg (dose ratio 5:4) in capsules was administered to ten patients undergoing hysterectomy for uterine leiomyoma. Each patient received a total of 3 of these Kelfiprim capsules: 2 capsules in a single administration 36 hours before surgery and 1 capsule 24 hours later. TMP and SMP concentrations were analyzed in plasma and also in the ovary, Fallopian tube and uterus, removed during surgery. The results indicated that in the reproductive organs of the female genital tract TMP reaches the same concentrations as in plasma. In contrast SMP is 3 to 3.5 times less concentrated in these tissues compared with plasma. At the TMP/SMP ratios obtained in these various organs synergism of the two compounds is reported to be particularly prominent for most bacterial strains. These findings indicate that this TMP-SMP combination may be useful in the treatment of female reproductive tract infections.

Neuronal localization and motor effects of gastrin-releasing peptide (GRP) in rat uterus

All parts of the internal female reproductive tract of the rat contained nerve fibers with immunocytochemically visible gastrin-releasing peptide (GRP)-like material. GRP-like immunoreactivity was also seen in nerve cell bodies of the paracervical ganglion formation, which in addition, harboured GRP nerve fibers. Pharmacological experiments were performed on isolated uterine and cervical smooth muscle tissue from two groups of spayed animals, one of which received estradiol. Both GRP and its non-mammalian counterpart, bombesin, evoked concentration-dependent clonic contractions in uterus and cervix, most pronounced in the estrogen-treated animals. Bombesin induced a stronger contractile force than GRP. The responses were not affected by tetrodotoxin. The observations suggest that GRP may be one of several neural messengers involved in the control of uterine motor activity.

An indwelling catheter for the collection of cat uterine fluids

A catheter system is described which allows for repeated samplings of uterine fluids in an awake animal. At laparotomy, catheters were inserted surgically into the ovarian pole of each uterine horn. The catheter ports then were passed through the abdominal wall through a stab incision and tunneled subcutaneously to a midlumbar position on each flank. The common uterine body was ligated to form a closed compartment. Uterine fluids were collected by saline lavage. Approximately 80% of the saline injected into one port was collected from the contralateral port and the catheters functioned successfully in each animal for approximately 45 repeated samplings.

An automatic multidimensional chromatography system for purification of human uterine progesterone receptor and induction of polyclonal antibodies

This paper reports on the synthesis of Org2058-bonded microparticulate silicas and their use in affinity chromatography as the first step for the purification of human progesterone receptor. The development of microprocessor-controlled instruments allows all the various steps to be performed automatically. The various steps used for the purification of human progesterone receptor were carried out with the FPLC system: affinity chromatography, desalting of eluate on Sephadex G-25, anion-exchange chromatography using a Mono Q column. With this procedure the receptor was purified approx. 10,000-fold within 24 h. The yield of receptor was generally 85-95%. Investigations with induced anti-progesterone receptor antibodies obtained after the fourth immunization show their immunoreactive behaviour towards progesterone receptor in crude cytosol, which was proved by sucrose density gradient centrifugation and by gel filtration on the FPLC system using a Sepharose 12 column. This implies that progesterone receptor was efficiently purified by our purification procedure.

Glycoproteins in rabbit uterus during implantation. Differential localization visualized using 3H-N-acetyl-glucosamine labelling and FITC-conjugated lectins

The synthesis of glycoproteins in rabbit uterine epithelium during the late preimplantation period was studied using tritiated N-acetylglucosamine. In vivo labelling was achieved by the intra-uterine implantation of agar gel columns containing the precursor. Autoradiography showed the radioactivity to be predominantly localized in the apical cell surfaces, with single cells exhibiting an accumulation of silver grains in their supranuclear cytoplasm. After gel electrophoresis of uterine flushings, activity was mainly found in the beta-glycoprotein fraction. Fluorescein isothiocyanate (FITC)-conjugated wheat-germ agglutinin reacted with the apical cytoplasm and surfaces of the endometrial cells. However, FITC-conjugated concanavalin A exhibited a different binding pattern, reacting first with the basal cytoplasm, and later with the apical cytoplasm. After concanavalin-A staining, single cells exhibited positive vesicles in their lateral and apical parts. These cells may be released into the uterine lumen until 210 h post column. Neither of the lectins reacted with ciliated cells. Concanavalin A showed an affinity for the beta-glycoprotein fraction of the uterine secretion. The results indicate that, although all endometrial cells contain glycoproteins, only a few of these seem to be involved in the synthesis of secretory products.

Copper and zinc content of human leiomyomas

The copper and zinc levels of leiomyomas were determined and compared to the levels in the uninvolved myometrium and myocervix. In general the levels found in leiomyomas were similar to those of the smooth muscle of isthmus and corpus but different to those of the myocervix. There were no significant differences in the levels found in smooth muscle of uteri with or without leiomyoma.

A cytosolic binding protein for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the uterus and deciduoma of rats

The cytosol fraction of the uterus of proestrous rats and of deciduoma specifically binds 3H-2,3,7,8-tetrachlorodibenzo-p-dioxin (3H-TCDD). The 3H-TCDD binding protein has a sedimentation coefficient of 9 S in low ionic 10-40% sucrose density gradients. The binding of 3H-TCDD in the 9 S region is abolished by a 500-fold molar excess of unlabeled benzo[a]pyrene, 3-methylcholanthrene or by a 100-fold molar excess of unlabeled TCDD. Incubation of the binding protein with TCDD in amounts in excess of 500 nM causes aggregation of the TCDD binding protein. Neither estradiol, progesterone, testosterone, dihydrotestosterone nor cortisol competed with TCDD in binding to this 9 S protein. The decidual tissue contains two binding components for TCDD as shown by Scatchard analysis. One of the components has a high affinity for TCDD (Kd = 1.68 nM) and is saturable. The number of binding sites is about 75 fmol/mg protein. The TCDD binding protein eluted through a DEAE-cellulose column using a gradient of 0.25 M KCl. The binding of estradiol and progesterone to their respective receptors was not affected by TCDD or by other polycyclic aromatic hydrocarbons as shown by sucrose density gradients and by microtiter competition assays. These results suggest that TCDD acts by binding to its own receptor system in the target tissue and not by competing with estrogen or progesterone for binding to their receptors. The possible role of the receptor in teratogenesis is discussed.

On the mechanism of opioid-oestradiol interactions

Characteristics of opioid binding and possible relationships between oestradiol and opioid binding sites were studied in rat oestrogen sensitive tissues(uterus, preoptic area-anterior hypothalamus, median eminence-basal hypothalamus). Naloxone (Nal) and oestradiol (Oe) bindings were assessed by in vitro saturation analyses. In 800 g supernatants of both uterine and hypothalamic tissues homogenates high affinity (Kd: 2-4 X 10(-9) M) and low capacity [3H]Nal binding sites were found. These binding sites were sedimented from 800 g supernatant by further centrifugation at 10(5) g for 1 h. In competition studies [3H]Nal binding was completely prevented by morphine, while met-enkephalin and leu-enkephalin caused only a partial inhibition. [3H]Nal binding was increased by ovariectomy and decreased by Oe treatment (10 micrograms/100 g b.wt) in both tissues. The cytoplasmic [3H]Oe binding in the studied tissues seems to be affected by the naloxone binding system. After in vitro saturation of naloxone binding sites by naloxone the [3H]Oe binding to low affinity sites (type II) in hypothalamus as well as in uterus has been increased by 8- and 2-fold, respectively. These results indicate the presence of specific [3H]Nal binding in rat uterus with similar properties to those found in the hypothalamus. Furthermore an interaction between opioid and oestradiol receptor systems could be also suggested.

Qualitative and quantitative distribution of plasminogen activators in organs from healthy adult mice

Twenty organs from healthy adult mice were tested for plasminogen activator activity. All were positive although specific activities varied 200-fold. Tissues with high activity were lung, uterus, brain and kidney. Endocrine glands were moderately rich in activator activity, and lymphoid tissues were poor. Molecular mass characterization was carried out. Two enzymatic forms were observed in all twenty organs: a 70 kDa form similar to human tissue plasminogen activator and a 48 kDa form analogous to mouse urokinase.

Protein method influences on calculation of tissue receptor concentration

Many protein methods are used for estimation of tissue receptor concentration. The authors compared performance, analytic variability, and accuracy of six protein methods used in these calculations. They found the Lowry protein procedure standardized with bovine serum albumin (BSA), usually considered the reference method, to be the most imprecise and most time consuming method. When the BSA standards from the Lowry procedure were assayed with the other methods, results ranged from 74 to 141% of expected. For three other protein standards, reactivity among the six methods varied almost twofold. Comparison of Lowry protein concentrations in cytosols from 46 tumors biopsies with other methods indicated best agreement was with an automated turbidometric (TCA) or a Coomassie dyebinding procedure. Use of protein standardization for the two direct spectrophotometric procedures decreased overestimation of receptor protein concentrations. Because receptor concentration is the quotient of receptor quantity and protein concentrations, tissue receptor results are dependent in part on standardization and choice of protein method.

Structure and dynamics of the estrogen receptor

To evaluate the structure and function of estrogen receptor (ER) in various mammalian systems, the cytosolic forms of receptor from calf uterus and from MCF-7 human breast cancer cells have been purified to virtual homogeneity by sequential selective adsorption to estradiol-Sepharose and heparin-Sepharose. In both cases, the purified steroid-receptor complex appears to exist as an activated 5S homo- or heterodimer of mol. wt 65,000 (4S) steroid-binding subunits. Purified ER has high affinity for DNA and serves as a substrate for phosphorylation by a purified rat brain kinase. Several monoclonal antibodies prepared against affinity-purified MCF-7 cytosol ER have been used to localize receptor by an indirect immunoperoxidase technique in fixed, frozen sections of human breast tumors, human uterus, rabbit uterus and in other mammalian reproductive tissues and cancers, as well as in fixed MCF-7 cell cultures and in paraffin-embedded sections of breast tumors and human endometrium. In all cases, we have observed only nuclear localization of immunoreactive receptor in tissues and whole cells, even under conditions in which virtually all of the receptor is found in a low-salt extract (cytosol) of the target cells. Treatment of cells or tissues in vivo or in vitro with estradiol alters the intensity but not the distribution of specific staining for ER. By immunoelectron microscopy, receptor was localized in the euchromatin, but not in the marginated heterochromatin or nucleoli of MCF-7 nuclei and epithelial and stromal nuclei of postmenopausal human endometrium. These observations suggest that the majority of the unoccupied receptor may actually reside in the nucleus, rather than in the cytoplasm as previously thought. Thus, hormone action may involve binding of the steroid directly to receptor loosely associated with nuclear components, followed by conversion of the steroid-receptor complex to an activated form which becomes more tightly associated with chromatin.

Immunocytochemical localization of corticosteroid-binding globulin in rat tissues

Previous studies utilizing steroid-binding assays have suggested that corticosteroid-binding globulin (CBG)-like glucocorticoid binding sites are present in various tissues of the rat. It is not known, however, whether such binding reflects the intracellular presence of CBG derived from serum or a special class (type III) of receptors. In order to elucidate this problem, immunocytochemical localization of rat CBG was carried out using a specific antiserum prepared against rat serum CBG and the peroxidase-antiperoxidase technique. Positive staining was found in certain cells of the liver, the distal and/or convoluted tubules of the kidney, the uterus, the follicular cells of the thyroid, and some cells of the anterior pituitary. Other tissues including heart, muscle, thymus, hypothalamus, supraoptic and paraventricular nuclei, and diaphragm were negative. The presence of immunoreactive CBG in specific cells of some glucocorticoid-responsive tissues and not others raises interesting questions concerning the transport of glucocorticoids and their mechanism of action.

Estrogen-induced protein in the rat uterus: association with actin

The affinity of the estrogen-induced protein, IP, for reconstituted F-actin in uterine homogenates was investigated. The results demonstrate that a significant proportion of a 46 K protein, of which the rate of synthesis is increased by estrogen, two properties of BB-CK, co-sedimented with in vitro re-polymerized actin.

Analysis of rat uterine estrogen receptors by high-pressure liquid chromatography methods

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.

Primary structure of rabbit lung uteroglobin as deduced from the nucleotide sequence of a cDNA

Double-stranded cDNA was synthesized from partially purified uteroglobin mRNA from rabbit lung. A cDNA coding for lung uteroglobin was then cloned in the plasmid pUC18 and both the nucleotide sequence and the derived amino acid sequence were determined. This allowed us to demonstrate unequivocally that uteroglobins from lung and uterus are identical proteins.

Estrogen and antiestrogen binding to rat uterine and pituitary estrogen receptor: evidence for at least two physicochemical forms of the estrogen receptor

Our laboratory has previously reported that calf uterine cytosol prepared in buffer containing 10 mM molybdate and chromatographed on DEAE-Sephadex contains two forms of the unactivated estrogen receptor, Peak I and Peak II; however, cytosol receptor bound to the high-affinity antiestrogen, H1285 (4-(N,N-diethylaminoethoxy)-4'-methoxy-alpha- (p-hydroxyphenyl)-alpha'-ethylstilbene), eluted only as Peak I. We have extended these studies to the rat uterus and pituitary in order to determine the organ and species specificity of this phenomenon. Cytosol prepared in Tris-molybdate buffer from immature and adult rat uteri or pituitaries was labelled with 10 nM [3H]estradiol or [3H]H1285 and chromatographed on QAE-Sephadex. Uterine estrogen receptors bound to either [3H]estradiol or [3H]H1285 eluted from QAE-Sephadex as a large Peak I (approximately 0.21 M KCl) and a smaller Peak II (approximately 0.25 M KCl). Analyses of these partially purified estrogen receptor fractions using high-salt sucrose density gradients showed that Peak I [3H]estradiol-receptor complexes sedimented predominantly as a lighter form (4.0S). In contrast, Peak I [3H]H1285-receptor complexes sedimented primarily as a heavier form (5.5S) often accompanied by a smaller lighter form (4.0S). Peak II [3H]estradiol- and [3H]H1285-receptor complexes sedimented as the heavier form (5.3-5.5S). These data suggest a monomer-dimer relationship between estrogen receptor forms with antiestrogen binding favoring the formation of the dimeric form. Further analysis of these Peak I receptor complexes by gel filtration chromatography yielded molecular forms of approx 70 KDaltons for [3H]estradiol-receptor complexes and 73 KDaltons and 165 KDaltons for [3H]H1285-receptor complexes, supporting the monomer-dimer concept. Data from experiments with the pituitary also suggest that H1285 causes the formation of the dimeric receptor form whereas estradiol interaction with the receptor results only in the monomeric form. These differences in estrogen receptor forms when bound by estrogen versus antiestrogen may be related to the different biological responses induced by these ligands.

Progesterone receptors in rat brain and uterus: dependence on the hormonal milieu

Cytosols were incubated from the hypothalamus and mid-brain and from the uterus, and incubated with [3H]progesterone alone or in the presence of excess radioinert steroid to reveal saturable binding sites. Bound and free hormone were separated by gel filtration. Scatchard analysis of the binding sites yielded evidence for only one class of binding sites of high affinity and limited capacity. The binding components in the hypothalamus and uterus appeared to fluctuate during the oestrous cycle, attaining a nadir at metoestrus, while those in the mid-brain were apparently unchanged. During pregnancy hypothalamic [3H]progesterone-binding sites appeared to lose affinity for the steroid while in the uterus the affinity for the steroid was unchanged but the absolute numbers of binding sites were greatly increased at day 10. It is concluded, both from studies of the properties intrinsic to the binding reaction and from endocrine correlates, that the macromolecular progesterone-binding components in the brain may be receptors for the hormone and that there may be differences between the properties of progesterone receptors in different tissues. Furthermore, during pregnancy there may be qualitative changes in the neural progesterone receptors which are not mediated by oestradiol.

Identification of immunoassayable estrogen receptor lacking hormone binding ability in tamoxifen-treated rat uterus

Using two different monoclonal antibodies to human estrogen receptor (ER), the enzymeimmunoassay was performed. The values of ER contents in human breast cancer and untreated rat uteri obtained by this procedure were correlated well with those by [3H] estradiol binding assay. When estradiol was injected to immature rats, the enzymeimmunoassay showed the uterine receptor dynamic pattern similar to those analyzed by exchange assays. In contrast, tamoxifen administration induced the immunoassayable but nonsteroid binding form of ER. This ER-like antigen was the heat-labile molecule with the sedimentation constant of 7 S while ER in untreated rat uterine cytosol sedimented at 9 S. These results suggest the presence of unique molecular state of ER induced by tamoxifen.

Preparation of a gap junction fraction from uteri of pregnant rats: the 28-kD polypeptides of uterus, liver, and heart gap junctions are homologous

A procedure for the preparation of a gap junction fraction from the uteri of pregnant rats is described. The uterine gap junctions, when examined by electron microscopy of thin sections and in negatively stained preparations, were similar to gap junctions isolated from heart and liver. Major proteins of similar apparent molecular weight (Mr 28,000) were found in gap junction fractions isolated from the uterus, heart, and liver, and were shown to have highly homologous structures by two-dimensional mapping of their tryptic peptides. An Mr 10,000 polypeptide, previously deduced to be a proteolytic product of the Mr 28,000 polypeptide of rat liver (Nicholson, B. J., L. J. Takemoto, M. W. Hunkapiller, L. E. Hood, and J.-P. Revel, 1983, Cell, 32:967-978), was also studied and shown by chymotryptic mapping to be homologous in the uterine, heart, and liver gap junction fractions. An antibody raised in rabbits to a synthetic peptide corresponding to an amino-terminal sequence of the liver gap junction protein recognized Mr 28,000 proteins in the three tissues studied, showing that the proteins shared common antigenic determinants. These results indicate that gap junctions are biochemically conserved plasma membrane specializations. The view that gap junctions are tissue-specific plasma membrane organelles based on previous comparisons of Mr 26,000-30,000 polypeptides is not sustained by the present results.

Cholesterol in the plasma membrane of uterine epithelial cells: a freeze-fracture cytochemical study with digitonin

Freeze-fracture cytochemistry with digitonin has been used to examine the cholesterol content of the plasma membrane of uterine epithelial cells during the early stages of pregnancy in the rat. Lesions caused by digitonin complexing with cholesterol were seen on both lateral and apical portions of the membrane but tight junctions and desmosomes were lesion-free. Compared with day 1 of pregnancy, lesions on the apical plasma membrane were much more extensive and some were of different morphology on day 6 - the day of blastocyst implantation. We consider mechanisms of lesion formation and interpret the results to indicate a higher content and perhaps a different organization of cholesterol in the apical plasma membrane on day 6 of pregnancy. We also suggest how this increase may occur.

Content of the collagen and elastin cross-links pyridinoline and the desmosines in the human uterus in various reproductive states

During pregnancy the collagen content of the human uterus increases sevenfold and the elastin content increases fourfold to fivefold. The stable pyridinoline cross-link is found in uterine collagen at a level of 0.11 mol per mole of collagen. The same ratio, or a higher one, is found at the end of pregnancy, indicating that pyridinoline synthesis keeps pace with the rapid synthesis of collagen. This cross-link would participate in the maintenance of high mechanical strength of the uterus needed during parturition. Uterine elastin contains 2.4 residues of desmosine plus isodesmosine in 1000 residues of amino acids. This value falls to 0.95 at term, indicating that synthesis of desmosines does not keep pace with the synthesis of elastin. Therefore, desmosine measurements do not provide an accurate index of elastin changes in pregnancy. Collagen and elastin contents in nongravid uteri increase with successive pregnancies; the cross-links remain constant during this change.

Glycosaminoglycans of porcine uteri

Glycosaminoglycan fractions were obtained from the pronase digests of the endometrium and myometrium of porcine uteri. Their glycosaminoglycan compositions were determined by the use of specific mucopolysaccharide-degrading enzymes and nitrous acid. It was found that the endometrium contained chondroitin sulfates, dermatan sulfate and heparan sulfate and a smaller amount of hyaluronic acid, whereas hyaluronic acid and dermatan sulfate were the major glycosaminoglycans in the myometrium.

Evidence for the existence of des-Asp1-angiotensin II in human uterine and adrenal tissues

Renin is present in various tissues outside the kidney. In contrast, the levels of angiotensins (ANG), the active products of the renin-angiotensin system, have not been thoroughly evaluated in tissues. In this study, we demonstrated the presence of immunoreactive (ir) ANG I and ANG II in various human tissues by RIA. Of the tissues examined, uterine tissue contained the most ir-ANG II. Since the anti-ANG II antibody used had significant cross-reactivity with ANG III, high performance liquid chromatography was performed to separate ANG II from ANG III. The major portion of the ir-ANG II in the plasma was ANG II. In contrast, the major portion of the ir-ANG II in uterine tissue was determined to be ANG III, a known biologically active peptide. The adrenal gland and testis also contained ANG III. From these results, it can be postulated that ANG III may contribute to the biological activity of ANG in some tissues.

Isolation and localization of neurophysin-like proteins in rat uterus

Neurophysins are part of the prohormones for vasopressin and oxytocin, and are localized with these hormones in the magnocellular cells of the neurohypophysis. New techniques have identified neurophysins in other areas within and outside the central nervous system, and we report here the isolation of neurophysins from the uterus of the rat. Using immunohistology the neurophysin immunoreactivity was localized to the epithelial lining cells of the uterus, and using radioimmunoassay was also present in uterine fluid suggesting secretion into the uterine cavity. The amount of uterine neurophysin increased in response to administered estrogen and was especially elevated in the pregnant uterus. The neurophysin-like material isolated from the uterus was similar to neurophysins from the neurohypophysis by radioimmunoassay, molecular sieve chromatography, isoelectric focusing and SDS gel electrophoresis. Both neurohypophyseal hormones, vasopressin and oxytocin, were also extracted from uterine endothelium and identified by radioimmunoassay and high pressure liquid chromatography.

Effect of partial stepwise luteectomy in pregnant gilts on maternal and fetal concentrations of progesterone

The number of corpora lutea (CL) in gilts was reduced to 8, 5, and 3 on Days 30, 40, and 50 of gestation, respectively. In a second group of gilts the number of CL was reduced to 5 by luteectomy by Day 50. Luteectomy did not affect concentrations of progesterone (P) in maternal uterine or fetal umbilical vessels sampled at Day 80. Concentration of P was higher in umbilical than uterine plasma in all treatments (P less than 0.01). The uterine arterial-venous (A/V) difference in concentrations of P was positive and the umbilical A/V difference was negative in all groups. The uterine and umbilical A/V differences at Day 80 decreased as the number of CL decreased. Fetal survival was reduced in luteectomized gilts. These results indicate that gradual reduction of numbers of CL does not result in placental secretion of P into the maternal circulation but does alter the uptake of P by the uterus and umbilical circulation.

Levels of neural vasoactive intestinal polypeptide in rat uterus are markedly changed in association with pregnancy as shown by immunocytochemistry and radioimmunoassay

Immunocytochemical studies have shown that the rat uterus is well innervated by nerve fibers containing vasoactive intestinal polypeptide (VIP). The fibers were associated with both vascular and nonvascular smooth muscle cells, and they were somewhat more numerous in the cervix compared to the uterine horns. This was confirmed in radioimmunologic determinations. Pregnancy induced a marked, almost 50% reduction in the total content of VIP in the uterine horns, which was associated with an almost complete disappearance of immunocytochemically visible nerve fibers in this part of the uterus. The innervation normalized within 25 days following delivery. Less marked changes occurred in the VIP innervation of the cervical region, where the concentration of the peptide was reduced mainly as a result of the increased tissue weight during pregnancy.

Uterotropic hormones produced by ovaries of Sl/Slt mutant mice before spontaneous development of tubular adenomas

Tubular adenomas developed spontaneously in ovaries of (WB X C57BL/6)F1-Sl/Slt and -W/Wv mice after 150 days of age. The uteri of the W/Wv mice were hypoplastic before development of tubular adenomas, but the uteri of the Sl/Slt mice were not. Since oophorectomy significantly reduced the uterus weight in the Sl/Slt mice, we investigated the androgen- and estrogen-producing activity of Sl/Slt and W/Wv mice before development of tubular adenomas. Fragments of ovaries were cultured for 48 hr in serum-free medium containing either progesterone or 4-androstene-3,17-dione (androstenedione). The amount of androgens produced from progesterone by ovaries of Sl/Slt mice in the presence of human chorionic gonadotropin was comparable to that of W/Wv mice. In contrast, the amount of estrogens produced from androstenedione by ovaries of Sl/Slt mice in the presence of follicle stimulating hormone was much greater than that of W/Wv mice. Moreover, the amount of estrogens produced was much greater than the amount of androgens in the ovaries of Sl/Slt mice. Therefore, before development of tubular adenomas, estrogens rather than androgens seem to be a major uterotropic hormone produced by ovaries of Sl/Slt mice.

Multiple extractions of hormone receptor from rabbit uteri and human breast tumors

The cytosol hormone receptors were extracted from rabbit uteri and human tumors with tris buffer systems for three consecutive homogenization and centrifugation processes to obtain three cytosols C-1, C-2, and C-3. The assay results evaluated revealed that minimal to tremendous amounts of receptor activities were present in C-2 and/or C-3 fractions. The essential experimental conditions and some speculative mechanisms have been discussed in detail.

Effect of ribonuclease on the physico-chemical properties of estrogen receptor

Estrogen receptors (ER) from rat and rabbit uterine cytosol were examined for their sensitivity to ribonuclease (RNase). After RNase treatment, a major part of rabbit uterine ER was converted from the 7S to 3-4S form, and its binding to DNA-cellulose was increased by 40%. Similar treatment on rat uterine ER showed a shift from 7S to 4.5S, and the DNA-cellulose binding was stimulated by 20%. Measurement of endogenous RNase levels showed that lower RNase concentration in rabbit uterine cytosol coincided with larger stimulation of DNA-cellulose binding by exogenous RNase. These results indicate that a major part of 7S ER is susceptible to RNase, and cleavage of bound RNA seems to uncover additional binding sites for DNA. In contrast to the general thinking that 4S to 5S transformation is essential for nuclear binding, we have observed that RNase-treated rat uterine ER did not undergo such a transformation by warming at 25 degrees C, while DNA-cellulose binding of the receptors increased. Thus, temperature activation could occur independent of 4S to 5S transformation.

Isolation of unliganded steroid receptor proteins by high-performance size-exclusion chromatography. An investigation of steroid-dependent structural alterations

The physicochemical properties of unliganded steroid receptor proteins remain largely unknown primarily due to receptor lability in the absence of specific ligand, especially during prolonged biochemical analyses. We have utilized high-performance size-exclusion chromatography (HPSEC) as a rapid means of investigating the structural properties of cytosolic estrogen receptor proteins in both the presence and absence of [3H]estradiol-17 beta. Cytosols prepared from immature calf uteri were analyzed by HPSEC on an Altex TSK-3000 SW column (600 mm X 7.5 mm I.D.) either before or after incubation with 10 nM [3H]estradiol-17 beta. Postcolumn detection of previously unliganded receptor was accomplished by incubation of fractions (0.38 ml) with 10 nM [3H]estradiol-17 beta for 2-18 h at 0 degrees C. Receptor-bound steroid was separated from free steroid by incubation with small pellets of hydroxylapatite. Nonspecific binding of [3H]estradiol-17 beta in parallel fractions was estimated using an unlabelled competitor (diethylstilbestrol) specific for the estrogen receptor. In low ionic strengths the receptor exists as a single, relatively stable, large form (retention time 34 min). The elution properties of this receptor configuration do not depend on bound steroid ligand. Analysis of receptor at elevated ionic strengths in the presence and absence of steroid ligand suggests that the salt-induced dissociation of receptor components to smaller forms (retention time 47 min) may be partially steroid-dependent. Characterization of receptor in 6 M urea demonstrates the presence of intermediate-sized receptor components (retention time 36-38 min). Analyses of receptor in 6 M urea-0.4 M potassium chloride suggests an inhibition of the more extensive salt-induced dissociation event seen in 0.4 M potassium chloride alone. Furthermore, the intermediate-sized receptor forms seen under these conditions (retention time 41-42 min) are generated in a steroid-dependent manner. The preparation of different molecular forms of biologically active, unliganded estrogen receptor by HPSEC should help further our investigations into the molecular mechanism(s) by which steroid hormones exert their receptor-mediated effects on target cells.

High-performance chromatofocusing of steroid receptor proteins in the presence and absence of steroid. Investigation of steroid-dependent alterations in surface charge heterogeneity

We have previously reported the development of high-performance chromatofocusing (HPCF) systems for rapid evaluation of the surface charge heterogeneity of steroid receptor proteins, each in the presence of its specific steroid ligand. However, the surface charge properties of ligand-free receptor proteins remain largely unknown. We have now employed HPCF to rapidly evaluate the surface charge properties of cytosolic estrogen receptor proteins in both the presence and absence of the ligand ([3H]estradiol-17 beta). All operations were performed at 0-4 degrees C. Cytosols prepared from immature calf uteri were preparatively analyzed by HPCF on a SynChropak AX-500 column (25 cm X 4.6 mm I.D.) either before or after incubation with 5-10 nM [3H]estradiol-17 beta. Elution of receptor was by generation of internal pH gradients (pH 8.1 to 3.2) using Pharmacia Polybuffers 96 and 74. Postcolumn detection of previously unliganded receptor was accomplished by incubation of pH-neutralized (pH 7.4) fractions with 5 nM [3H]estradiol-17 beta in the presence and absence of unlabelled competitor. Specifically bound steroid was determined in each fraction using an hydroxylapatite adsorption assay. Significant surface charge heterogeneity was observed for both unliganded receptor and the steroid-receptor complex. The heterodisperse pattern of receptor surface charge appeared to vary in a steroid-dependent manner. Preformed steroid-receptor complexes eluted primarily between pH 6.5-7 and between pH 5-6, with indications for heterogeneity within both regions. The surface charge distribution of unliganded receptor routinely revealed additional, more acidic eluting (pH 3.8-4.6) receptor forms. Sodium molybdate, a commonly used receptor-stabilizing agent, maintains receptors during HPCF as relatively acidic eluting forms (pH 3.8-5.0). The specific elution profile of molybdate-stabilized receptor also appears steroid-dependent. These data demonstrate that HPCF can be used preparatively to rapidly isolate unliganded receptor forms in a biologically active state.

Opposing biological actions of antiestrogens in vitro and in vivo: induction of progesterone receptor in the rat and mouse uterus

The nonsteroidal antiestrogen tamoxifen, 4-hydroxytamoxifen, and Ly117018 inhibited the estradiol-stimulated induction of progesterone receptors in primary cultures of immature rat uterine cells. This effect was found to be completely reversible with increased concentrations of estradiol. These compounds possessed no estrogenic activity. In contrast, ICI 47,699 (the cis geometric isomer of tamoxifen) and ICI 77,949 (tamoxifen without the dimethylaminoethyl side chain) were fully estrogenic, and bisphenol (4-hydroxytamoxifen without the dimethylaminoethyl side chain) possessed mixed estrogenic/antiestrogenic activity. In primary uterine cell cultures derived from mature ovariectomized mice, 4-hydroxytamoxifen was, again, nonestrogenic and inhibited the estradiol-stimulated induction of progesterone receptors. The antiestrogenic activity of 4-hydroxytamoxifen was effective against both steroidal and nonsteroidal estrogens in either rat- or mouse-derived uterine cell cultures. Using the 3-day uterine assay in vivo, 4-hydroxytamoxifen partially stimulated progesterone receptor induction in the immature rat, whereas it fully stimulated the same end point in the mature ovariectomized mouse. These results emphasize the difference between antiestrogen activity in vivo and in vitro, and also indicate that the increased agonist activity of 4-hydroxytamoxifen in the mouse compared to that in the rat in vivo is not reflected in vitro. Therefore, we have extended the model of antiestrogen action previously described in primary pituitary cell cultures to progesterone receptor induction in two murine uterine cell cultures.

The immunocytochemical localization of a cat uterine protein that is estrogen dependent (CUPED)

An estrogen-dependent polypeptide (CUPED), which was purified from uterine flushings of estrogen-treated cats, was localized in endometrial epithelial cells of cats using the peroxidase-antiperoxidase immunocytochemical staining procedure. Epithelial cells from animals treated with estradiol for 4, 7, or 14 days and estrogen-primed animals treated with progesterone for 2 days showed positive immunostaining. Staining was absent in untreated ovariectomized animals and in estrogen-primed animals treated with progesterone for 4 days. Specific cytoplasmic staining was confined to apical secretory granules in nonciliated cells of deep uterine glands. Staining was also commonly observed in the lumen of deep glands. Immunostaining was absent in the cells of the surface epithelium, stroma, and myometrium. In addition, other organs such as the oviduct, kidney, liver, pancreas, and lung showed no evidence of specific immunocytochemical staining. Therefore, the estrogen-dependent polypeptide obtained from uterine flushings of estrogen-treated ovariectomized cats is a uterine-specific secretory product that is packaged in apical cytoplasmic granules of uterine epithelial gland cells before being released into the uterine lumen.

Electrophoretic analysis of the estrogen receptor. Molybdate stabilization and identification of the classical estrogen receptor

Conditions are defined which permit analysis of estrogen receptors from the mammalian uterus by polyacrylamide gel electrophoresis, thereby solving a longstanding problem encountered in previous attempts at such analysis, namely the failure of a large portion of the receptor population to enter such gels. A paramount requirement for entry of the estrogen-receptor complex into polyacrylamide gels is its maintenance in an untransformed state which does not form aggregates that are excluded from these gels. Of the multiple estrogen-binding proteins separated, only one (relative mobility of 0.5-0.6) possessed the definitive characteristics of the classical estrogen receptor. The inclusion of molybdate in extraction buffers selectively enhanced receptor recovery and facilitated its separation. Moreover, the estrogen-receptor complex so resolved is separated from other types of estrogen-binding proteins present in the uterine cytosol. These findings show that the molybdate-stabilized estrogen receptor exists in a single discrete form, but otherwise exhibits multiple forms that are probably artifactual. Electrophoresis in discontinuous buffers, but not in a continuous buffer system, promoted aggregate formation. This finding has implications concerning the subunit structure of the untransformed receptor.

Prenatal diethylstilbestrol exposure alters murine uterine responses to prepubertal estrogen stimulation

Prepubertal estrogen stimulation was used to investigate the effects of prenatal diethylstilbestrol (DES) exposure on subsequent growth, secretory activity, and cellular differentiation of the mouse uterus in vivo. Secretory activity was examined using sensitive silver staining of two-dimensional gel electrophoresis of uterine luminal fluid (ULF). Decreased uterine growth response, decreases in ULF quantity and protein concentration, alterations in specific ULF proteins, and altered cellular differentiation were found. This system provides a method for evaluation of the effects of prenatal exposure to DES or other compounds on the estrogen-induced secretory activity of the uterus. The alterations found in this study may be partially responsible for the decreased fertility in this mouse model and may have implication for DES-exposed women.

Particulate nature of the unoccupied uterine estrogen receptor

Homogenization of rat uteri at 25 degrees C resulted in a particulate partitioning of the estrogen receptor. Homogenization at 0 degrees C, the use of frozen tissue, or the pre-exposure of the tissue to 0 degrees C prior to 25 degrees C homogenization induced soluble partitioning of the estrogen receptor. Binding of a radiolabeled monoclonal antibody indicated that, in absence of estradiol, the estrogen receptor is particulate and is associated with the nuclei-enriched fraction of the target cell. The presence of receptor in the soluble fraction thus appears to be an artifact of homogenization. The unoccupied receptor, loosely associated with the particulate fraction (cold-sensitive) represents the "native" form of receptor which, upon arrival of the hormone, becomes tightly associated (cold-insensitive). The transition from the cold-sensitive to the cold-insensitive status is accompanied by a modification of the electrical charge of the receptor.

The use of the biotinyl estradiol-avidin system for the purification of "nontransformed" estrogen receptor by biohormonal affinity chromatography

Several biotinyl estradiol derivatives have been prepared by coupling estradiol 7 alpha-carboxylic acid to biotin via different linear linkers. All these compounds exhibit a high affinity for the estrogen receptor as determined by competitive binding assays against [3H]estradiol. These compounds also displaced the dye 4-hydroxyazobenzene-2'-carboxylic acid from the biotin-binding sites of avidin free or immobilized on agarose. It was demonstrated that only the derivatives bearing a long spacer chain (greater than 42 A greater than) between estradiol and biotin were able to bind receptor and avidin simultaneously, suggesting some steric hindrance. The biotin-avidin system has been investigated for the purification of the cytosoluble "nontransformed" estrogen receptor stabilized by sodium molybdate. The method relies on: 1) high biohormonal affinity of receptor for biotinyl estradiol derivative; 2) the specific selection by avidin-agarose column of biotinyl estradiol-receptor complexes; and 3) the biohormonal elution step by an excess of radioactive estradiol. Starting from unfractionated cytosol containing molybdate-stabilized nontransformed 8S estrogen receptor with estradiol 7 alpha-(CH2)10-CO-NH-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-(CH2)3-NH-biotin, preliminary experiments using avidin-agarose chromatography and then a specific elution step by exchange with free [3H]estradiol, allowed a 500-1,500-fold purification. Further purification of estrogen receptor was obtained by ion exchange chromatography through a DEAE-Sephacel column and led to a congruent to 20% pure protein, assuming one binding site/65,000-Da unit. The hydrodynamic parameters of the purified receptor were essentially identical to those of molybdate-stabilized nontransformed receptor present in crude cytosol. The advantages of this double biotinyl steroid derivative-avidin chromatographic technique over more conventional affinity procedures are discussed and make it applicable to the purification of minute amounts of steroid receptors in a wide variety of tissues.

Regional changes in catecholamine content of the pregnant uterus

High-pressure liquid chromatography with electrochemical detection was used to identify and measure catecholamines in rat, rabbit, sheep, guinea-pig and human uteri and follow changes with pregnancy. Noradrenaline was consistently the major catecholamine and pregnancy caused a regionally specific fall in its concentration which, in rat, rabbit and guinea-pig, was associated with a decline in total content. Adrenaline was undetectable (less than 10 pmol/g myometrium) in all species and at all gestational ages studied. Dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) were detected at high concentrations in guinea-pig and particularly sheep uterus. In guinea-pig uterus the dopamine/DOPAC ratio fell dramatically with pregnancy, suggesting that increased quantities of dopamine were released and catabolized. The dopamine/noradrenaline ratios suggested that dopamine is stored with noradrenaline in adrenergic neurones in guinea-pig myometrium and within an additional neuronal or cellular store(s) in sheep uterus.

Comparison of media proteins from ovariectomized rat uteri following estrogen treatment

Ovariectomized rats were treated with estradiol for 3 days after which their uteri were incubated in vitro and radioactive media proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Media were also chromatographed on G-25 Sephadex Blue Sepharose columns to isolate subsets of proteins. The results demonstrate that two proteins are consistently increased following estrogen treatment. These proteins have molecular weights of 104,000 and 65,000. Neither protein binds to Blue Sepharose to a great extent. The use of the protein synthesis inhibitors, emetine and actinomycin D, demonstrates that the proteins are synthesized de novo. These two proteins may serve as markers for genomic response to estradiol in the rat uterus.

Progestin modulation of estrogen-dependent marker protein synthesis in the endometrium

While it is well known that progestins have significant effects on estrogen-dependent processes in the uterus, very little is known about the molecular details of these effects. To understand these processes we have developed an immunocytochemical staining technique to help clarify the progestin regulation of estrogen receptor (ER), and we have also studied the effects of progestins on estrogen-dependent specific protein synthesis and secretion in the immature rat uterus. The immunocytochemical method for identifying estrogen receptor in tissue sections uses biotinylated monoclonal antibody to the estrogen receptor protein and shows a largely nuclear localization of the receptor protein in the rat uterine endometrium and myometrium. This method can be used to explore changes in the intercellular and intracellular localization of the uterine ER during progestin action. In an effort to correlate these changes with specific biological responses in the uterus we have been studying the effects of the administration of estrogens and progestins in vivo on the synthesis of specific proteins in uterine target cells in vitro. We previously reported that one-dimensional SDS-PAGE analysis of labeled secreted uterine proteins and cellular proteins extracted from the luminal epithelium and from the stroma plus myometrial fractions of the uterus revealed that estradiol-17 beta preferentially stimulated the synthesis of 110,000, 74,000, and 66,000 dalton secreted proteins, and 180,000 and 110,000 dalton epithelial proteins. We found that while progestins administered alone in vivo did not have any stimulatory effect on the synthesis of these secreted or cellular uterine proteins, concomitant administration of either progesterone or megestrol acetate and estradiol in vivo substantially reduced the estrogen-stimulated increase in labeling of the 110,000, 74,000, and 66,000 dalton secreted uterine proteins in vitro. In animals first primed with the progestin prior to combined estrogen/progestin treatment, the progestins were even more effective antagonists of estrogen. In addition, progestins alone given 24 hours after estradiol substantially inhibited the estrogen-stimulated synthesis of these proteins. These results suggest that progestins can both modulate the initial level of estrogen stimulation of synthesis of specific proteins and selectively terminate their synthesis, by affecting the continued transcription of their estrogen-regulated genes, altering the processing, half-life, or translation of their mRNAs, or by modulating the translation or the posttranslational processing of the nascent peptide chains.

Electrophoretic characterization of purified bovine, porcine, murine, rat, and human uterine estrogen receptors

The calf uterine estrogen receptor (E2R) in the presence of sodium molybdate has been purified, 7,000-fold by a single passage over an estradiol affinity column. A dominant 70,000-dalton band and two minor bands at 50,000 and 30,000 daltons were observed by electrophoretic analysis. These bands had been eluted using estradiol, sodium sulfocyanate, CHAPS, and HEPES (pH 7.4) with insulin as a carrier protein. The identities of the protein bands were initially confirmed by their failure to bind the affinity column when saturated with estradiol. This single step purification procedure was reproducible and rapid, with yields of 10-20%, providing 25% purity. Diffusion blot analysis, with specific 35S- and 125I-labeled monoclonal antibodies to E2R, confirmed that the 70,000-dalton band represented the estrogen receptor. Specificity was demonstrated by inhibition of binding of purified E2R by both estradiol and diethylstilbestrol but not testosterone, progesterone, corticosterone, aldosterone, or hydrocortisone. The relative binding affinity of the purified receptor was: ethynyl estradiol greater than 17 beta estradiol greater than estriol greater than or equal to estrone greater than or equal to 17 alpha-estradiol greater than mestranol. Pig, human, mouse, and rat uterine estrogen receptors were similarly purified with the affinity column. As with the calf uterine preparations, a dominant 70,000-dalton band with minor bands at 50,000 and 30,000 daltons was identified by diffusion blot analysis in all the species examined.