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PubMed1991

Proteoglycan metabolism in the connective tissue of pregnant and non-pregnant human cervix. An in vitro study.

Profound changes occur in the cervix during pregnancy. In particular, the connective tissue is remodelled. To elucidate the mechanisms behind this process, the metabolism of cervical connective tissue was studied using tissue cultures. Cervical biopsies from non-pregnant and pregnant women were incubated with [35S]sulphate. The proteoglycans of the tissue specimens were purified by ion-exchange and gel chromatography and characterized by SDS/PAGE and by enzymic degradation. In the non-pregnant cervix, the incorporation of [35S]sulphate into the proteoglycans was linear for 48 h. During the first 6 h of incubation the accumulation of chiefly one small labelled proteoglycan (apparent Mr 110,000) substituted with dermatan sulphate was recorded. This is in accordance with the known proteoglycan composition of non-pregnant cervical tissue. In addition, small amounts of two larger radioactive dermatan/chondroitin sulphate proteoglycans (apparent Mr values 220,000 and greater than 500,000) were recorded. After longer periods of incubation the proportion of heparan sulphate proteoglycans increased considerably. The pregnant tissue showed a clearly different composition of labelled proteoglycans. An increased accumulation of the two larger dermatan/chondroitin sulphate proteoglycans was seen in addition to the dominant small dermatan sulphate proteoglycan of the non-pregnant cervix. The rate of accumulation of these two proteoglycans was about 3 times higher in the pregnant tissue, whereas that of the small dermatan sulphate proteoglycan was only increased 2-fold. The fact that the concentration of proteoglycans in the pregnant cervix is approximately one-half of that in the non-pregnant cervix indicates that the turnover of proteoglycans in pregnant cervical tissue is significantly increased. The major effect of this profound change of metabolism was a 50% decrease in proteoglycan content and a 2-fold increased proportion of a dermatan sulphate proteoglycan with an apparent Mr of 220,000.

Adult↗
PubMed1996

Evidence for the presence of a large keratan sulphate proteoglycan in the human uterine cervix.

Profound changes occur in the uterine cervix during pregnancy. In particular, the extracellular matrix of the connective tissue is remodelled extensively. To elucidate the mechanisms involved in this process, we have analysed the proteoglycan pattern in the human cervix from pregnant and non-pregnant women. Proteoglycans of the cervix tissue specimen were extracted with 4 M guanidine hydrochloride and precipitated with 80% ethanol. Purification of proteoglycans was performed by several chromatographic steps. Characterization of proteoglycans was done by SDS/PAGE before and after digestion with glycosaminoglycan-specific enzymes. Proteoglycans were detected by combined Alcian Blue/silver staining or, after blotting of biotin-labelled proteoglycans on to poly(vinylidene difluoride) membrane, with peroxidase-conjugated avidin or by the use of keratan sulphate- or decorin-specific monoclonal antibodies. In contrast with previous reports, where only chondroitin/dermatan sulphate proteoglycans have been found in the uterine cervix, we have shown in the present study the existence of a large keratan sulphate proteoglycan with an M(r) > 220,000 in cervix samples from non-pregnant and pregnant women. This proteoglycan showed a strong reaction with the keratan sulphate-specific monoclonal antibody 5D4 and could be degraded by keratanases. The size of the core protein of this keratan sulphate proteoglycan was estimated to be about M(r) 220,000.

Cervix Uteri↗
PubMed1990

[Principles of physiologic and drug-induced cervix ripening--recent morphologic and biochemical findings].

Maturation of the cervix during pregnancy is an essential pre-requisite for an uncomplicated delivery at term. Physiological cervical ripening is characterised by a diffuse loosening of the collagenous connective tissue with widely scattered collagen fibrils and an increased amount of extracellular ground substance. These morphological changes are similar to those after prostaglandin (PG)-pre-treatment of the cervix. The local application of PG leads to a marked mulifocal loosening of the collagen fibre bundles with "activated" fibroblasts, characterised by a fine granular loosening of the cytoplasm, vacuolised enlarged mitochondria and an increased number of cytoplasmatic vesicles close to the cell surface. In the course of pregnancy the volume of the cervix increases by a significant rise in synthesis of collagen, protein, glycosaminoglycan and fibronectin. The change in consistency during late pregnancy corresponds to a significant decrease in dermatan sulphate coninciding with a marked increase in hyaluronic acid concentration associated with increased water uptake. Contrary to the already published literature, enzymatic collagen degradation does not play an important role in physiological cervical maturation. The action of catabolic enzymes (collagenases, glycosidases), liberated from polymorphonuclear leukocytes invading the extracellular matrix, is responsible for the rapid dilatation of the cervix at parturition. This process is limited by the immediate postpartum insudation of the cervix by plasma containing highly potent proteinase inhibitors (e.g. alpha 2-macroglobulin). PG-induced cervical ripening is associated with a time-limited enzymatic collagen degradation, an increased synthesis of non-collagenous proteins and a significant increase in hyaluronic acid concentration. Our basic biochemical findings in cervical ripening and dilatation during parturition may greatly contribute to the development of new concepts in the causal treatment of cervical pathology during pregnancy.

Cervix Uteri↗
PubMed2002

Immunohistochemical distribution of oestrogen and progesterone receptors and tissue concentrations of oestrogens in the cervix of non-pregnant cows.

An immunohistochemical study of the expression of oestrogen (ER) and progesterone receptors (PR) in different regions along the longitudinal and vertical axes of the cervix of non-pregnant cows was performed. Animals were separated into two groups depending on the presence or absence of a functional corpus luteum in their ovaries, as indicated by blood progesterone concentrations. The high progesterone group (HP4) had serum progesterone concentrations > 2.0 ng mL(-1) (n = 6) and the low progesterone group (LP4) had serum progesterone concentrations < or = 0.5 ng mL(-1) (n = 4). Significantly higher concentrations of oestrogen were found in the cervical tissue of animals in the LP4 group than those in the HP4 group (473 +/- 53 v.149 +/- 46 pg g(-1) wet weight; P < 0.01). Furthermore, there was a significant effect of tissue layer (epithelium to deep stroma) on the number of ER (P < 0.01) and PR (P < 0.05) immunoreactive nuclei per 1000 cells. For both ER and PR the proportion of cells expressing the receptor increased from epithelium to subepithelial stroma (P < 0.01) and from subepithelium to deep stroma (ER P < 0.05; PR P =0.061). When the number of receptor-positive cells were expressed per mm2 tissue, differences between the subepithelial stroma and the deep stroma became even more marked. In addition, the vaginal part of the cervix had significantly more (P < 0.01) ER and PR immunoreactive nuclei per 1000 cells than the uterine part, but these differences were no longer apparent when a correction was made for cell density. There was no relationship between progesterone status of the animals, nor local tissue oestrogen concentrations and ER or PR immunoreactivity in the cervix of these non-pregnant cows. Instead, a strong relationship between both longitudinal and vertical positioning of tissue in the cervix and expression of both receptor types was shown. In addition, a strong correlation between ER and PR expression in the subepithelial stroma (R = 0.85, P < 0.01) and the deep stroma (R = 0.83 P < 0.01) was evident. In conclusion, these results demonstrate that in studies of steroid hormone receptor expression in the cervix, careful description of sampling site and depth are necessary if the results are to be interpreted meaningfully.

Animals↗
PubMed2004

HPV prevalence and concordance in the cervix and oral cavity of pregnant women.

OBJECTIVES: This investigation examined human papillomavirus (HPV) in pregnant women in order to characterize viral prevalence, types and concordance between infection in the cervix and in the oral cavity. METHODS: A total of 577 pregnant women seeking routine obstetric care were evaluated for HPV infection in their cervix during gestation and immediately before delivery, and in the oral cavity during gestation. Male partners present during the gestational clinic visit also provided a specimen from their oral cavity. HPV assessment was performed by PCR, dot blot hybridization and DNA sequencing. A sexual and health questionnaire was completed by the pregnant women. RESULTS: HPV prevalence in women was 29% in the cervix and 2.4% in the oral cavity. Among those with both gestational and delivery specimens, 35% were infected at least once and 20% had infection at both intervals. At delivery, 68% of infected women had an oncogenic HPV type in the cervix. There was no type-specific HPV concordance between the two cervical specimens, nor cervical and oral results in women, nor with cervical and oral findings between partners. CONCLUSION: The lack of association in HPV positivity and types between the cervix and oral cavity in these women suggests that self-inoculation is uncommon. This source of infection does not appear to be from oral contact with a current male partner, since there also was no concordance between partners. These results suggest either other modes of HPV transmission or differences in susceptibility to HPV infection or its clearance in the oral cavity and genital mucosa.

Adult↗
PubMed2003

Predictive value of two-dimensional and three-dimensional multiplanar ultrasound evaluation of the cervix in preterm labor.

OBJECTIVE: To compare the predictive value of conventional two-dimensional ultrasound measurement of cervical length and three-dimensional multiplanar volume assessment of the cervix for delivery at < 37 weeks of gestation among patients with preterm labor. MATERIALS AND METHODS: This preliminary prospective study was conducted in 28 patients hospitalized for preterm labor between 24(+0) and 33(+6) weeks of gestation, defined by regular and painful uterine contractions (at least two per 10 min), intact membranes and a cervical length of < or = 26 mm measured by two-dimensional transvaginal ultrasonography at admission with a Voluson 530 (Kretz, France) machine using a 7.5-MHz transvaginal transducer. The cervical volume was then assessed by the three-dimensional triplan technique. It was automatically calculated after drawing of the cervix outlines in mid-sagittal and median axial plane images. As the border between the cervix and the lower uterine segment is virtual, it was defined by a perpendicular line to the line joining the external os and the internal os. The result of the latter measurement was not disclosed to the obstetric team. The primary outcome was the rate of deliveries at < 37 weeks. We constructed a receiver operator characteristic (ROC) curve to determine the optimal cut-off point of the cervical volume, to predict preterm delivery. RESULTS: Sixteen (57%) patients delivered at < 37 weeks. Mean (+/- SD) gestational ages at admission and delivery were 28.2 (+/- 3.2) weeks and 35.9 (+/- 4.1) weeks, respectively. Mean cervical length and volume at admission were 20.1 (+/- 9.9) mm and 23.1 (+/- 14.6) mm3, respectively. The ROC curve showed that the optimal cut-off point was 20 mm3. The predictive values of cervical length and of cervical volume on delivery at < 37 weeks were: sensitivity, 87.5% (14/16) and 75% (12/16); specificity, 50% (6/12) and 75% (9/12); positive predictive value, 70% (14/20) and 80% (12/15); negative predictive value, 75% (6/8) and 69.2% (9/13), respectively. CONCLUSIONS: The three-dimensional multiplanar volume assessment of the cervix probably increases the positive predictive value of cervical ultrasonography in predicting preterm delivery. Screening high-risk women could be achieved by conventional two-dimensional transvaginal ultrasound and the diagnosis of true preterm labor may be improved by three-dimensional multiplanar transvaginal ultrasound assessment of the cervix.

Adult↗
PubMed2001

Magnetic resonance imaging of the human cervix: a study of the effects of prostaglandins in the first trimester.

BACKGROUND: To establish that magnetic resonance imaging (MRI) can provide an objective measurement of the biophysical state of the cervix and to measure the response of the cervix to prostaglandins in the first trimester of pregnancy. METHODS: A comparative study, with each patient serving as her own control, was carried out on 10 primigravid women with 49--84 days amenorrhoea undergoing surgical termination of pregnancy. Each woman had two MRI scans of the uterus and cervix. The first scan was performed prior to administration of prostaglandins and the second scan 2.5--3 h following an 800 microg dose of misoprostol given vaginally. Cervical change was assessed by measurement of cervical length, transverse diameter of the cervix, diameter of the internal os and cervical stromal signal intensity. RESULTS: A significant difference in cervical length (P = 0.012), transverse diameter (P = 0.001) and diameter of the internal os (P = 0.008) was detected following the administration of misoprostol. In five women a significant change in one or both components of the cervical stromal signal was detectable and in five women no change could be demonstrated. CONCLUSION: MRI is capable of detecting changes in the physical parameters of the cervix following administration of prostaglandin. However, the changes detected in the stromal signal intensity are less consistent. The potential of MRI as a clinical tool to monitor cervical changes in a variety of clinical situations warrants further investigation.

Abortion, Induced↗
PubMed2003

Collagen remodelling in the guinea-pig uterine cervix at term is associated with a decrease in progesterone receptor expression.

In human and guinea-pig parturition, progesterone withdrawal and estrogen action are not mediated by changes in their circulating levels. Instead, these events might be promoted by changes in the responsiveness of the uterus and cervix to progesterone and estrogen via changes in their receptors. In this study, the guinea-pig model was used to investigate whether high levels of progesterone and estrogen at term are associated with regional changes in PR and ERalpha levels in uterus and cervix. PR and ERalpha profiles were established in both subepithelium and the muscular layer of the cervix and the lower uterine horns during pregnancy, parturition and postpartum; while collagen remodelling was measured in the subepithelium. Our data showed that collagen remodelling involved in cervical ripening is temporally and spatially associated with a decrease in PR, whereas high expression of ERalpha is observed. This association was found in the subepithelium of the cervical tissue but not in the same region of the uterus. The muscular region of the cervix and uterus also present a transiently decreased expression of PR while ERalpha levels remain high. Thus, the present results indicate that, before parturition, diminished responsiveness of the cervix to progesterone might be caused by a decrease in PR levels and that this may be the mechanism of functional progesterone withdrawal. The guinea-pig was further validated as an animal model for human parturition studies.

Animals↗
PubMed2004

Diethylstilbestrol versus estradiol as neonatal disruptors of the hamster (Mesocricetus auratus) cervix.

The synthetic estrogen diethylstilbestrol (DES) is an established, estrogenic endocrine disruptor (ED). The Syrian golden hamster (Mesocricetus auratus) offers some unique advantages as an experimental system to investigate the perinatal ED action of DES and other estrogenic EDs. Previous analyses regarding the consequences of neonatal administration (100 microg) of DES versus estradiol-17beta (E2) showed that DES had a more potent disruptive effect on morphogenesis and gene expression in the uterus, oviduct, and ovary as well as in the testis and male accessory organs. The objectives of the present study were to describe the histopathological consequences of the two neonatal treatment regimens in the hamster cervix and to compare them with our previous observations in the hamster uterus. As previously found in the hamster uterus, DES was more potent than E2 as a neonatal disruptor of the hamster cervix in prepubertal animals and in ovarian-intact adult animals. However, the cervix-versus-uterus scenario diverged in animals that were ovariectomized prepubertally and then chronically stimulated with natural estrogen (E2). We confirmed previous observations that neonatal exposure to DES, but not to E2, permanently alters estrogen responsiveness in the adult hamster uterus, but neither neonatal treatment regimen affected estrogen responsiveness in the adult hamster cervix. These results suggest that an unidentified ovarian factor influences the extent of neonatal DES-induced disruption of the cervix, but not of the uterus, in hamsters.

Aging↗
PubMed1999

Macrophage trafficking in the uterus and cervix precedes parturition in the mouse.

Immune activation is implicated in the etiology of preterm labor, but little is known about macrophage number or distribution in the uterus or cervix at term. This study tested the hypothesis that macrophages migrate into the reproductive tract before the onset of parturition. Paraffin-embedded sections from the mid-uterine horn and cervix of C3/HeN mice on Days 15 and 18 of pregnancy, the day of birth (Day 19), and 1 day postpartum were stained with a pan-macrophage marker to analyze cell numbers and distribution. During pregnancy, uterine macrophages were dispersed in endometrium, usually associated with vasculature and subluminal epithelium. In myometrium, macrophages were clustered in stromal connective tissue; near term and postpartum, cells appeared to surround the muscle bundles. Total macrophage numbers were increased on Day 15 relative to those in nonpregnant controls, declined before birth, and increased postpartum. In the cervix, macrophages congregated in subepithelium, often perivascular or near ganglia. Macrophage numbers in the cervix peaked on Day 18, then declined to nonpregnant levels by the day after birth. Thus, macrophage numbers in the uterus were inversely related to those in the cervix. These findings raise the possibility that macrophages and their products may be involved in uterine contractility and cervical remodeling during the processes of parturition.

Animals↗
PubMed1983

Physical characteristics of the cervix.

The cervix must remain closed during pregnancy to maintain the pregnancy yet open during parturition. It must perform at the right time and in the right sequence. The process that coordinates these activities is labor and it is an equal mixture of uterine contractions and cervical effacement/dilatation. Neither of these factors can be ignored if one is to understand parturition. Dilatation of the cervix depends upon the biochemical and physical processes that produce effacement. A better understanding of this active, ongoing process will enable one to manipulate them with new drugs that could produce effacement without uterine contractions. Conversely, the capacity to "stiffen" the cervix to ward off premature birth is another potential therapeutic approach that may be utilized. Research into the genesis and physical expression of the incompetent cervix is needed, as are studies of the cervix after forceable dilatation following a D and C. All of these possibilities and future advances are dependent upon our ability to quantitate the physical state of cervical tissue, both in situ and in vitro.

Biophysical Phenomena↗
PubMed1993

Cervical contractions: the response of the cervix to oxytocic stimulation in the latent phase of labour.

OBJECTIVE: To assess the cervical response to myometrial activity in early labour. DESIGN: Prospective observational study. SUBJECTS: Women requiring oxytocin stimulation in induced and spontaneous labours. SETTING: A teaching hospital in Birmingham. MAIN OUTCOME MEASURES: Simultaneous comparison of the cervical response to myometrial contractions was made on a cycle by cycle basis to deduce the properties of the cervix in early labour. RESULTS: Sixty-seven patients have been monitored, of whom 63 had satisfactory cervimetry data. Thirty (47.6%) women exhibited cervical contractions in response to myometrial activity. This response was only observed at dilatations up to 4 cm. The change in behaviour coincides with the transition from latent to active phases of dilatation. The length of the latent phase of labour was significantly longer in those women who exhibited cervical contractions (P < 0.001), although the active phase was similar in the two groups (P > 0.1). The group without cervical contractions exhibited a greater degree of effacement (P < 0.05) and tended to have more dilated cervices (P < 0.01) than those who showed cervical contractions. CONCLUSIONS: It is possible for the cervix to contract in early labour. This response may be the result of incomplete preparation of the cervix for the process of dilatation, and is seen during what is recognised as the latent phase in those women in whom the cervix is unaffected and undilated. These properties of the cervix may explain the poor results obtained from oxytocin stimulation of labour in the latent phase.

Adult↗
PubMed1996

Colonization in the rectum and uterine cervix with group B streptococci may induce specific antibody responses in cervical secretions of pregnant women.

We have studied the relationships between genital or rectal carriage of group B streptococci (GBS) with the levels of systemic and mucosal antibodies to GBS in 200 women at about week 17 of pregnancy. Secretions from the uterine cervix were collected with absorbent cylindrical wicks for quantification of antibody levels with whole cell enzyme-linked immunosorbent assay. GBS were cultured from the cervix (with or without concomitant rectal colonization) of 13.5%, from the rectum (with or without concomitant cervical colonization) of 12%, and from both culture sites of 8.5% of the women. Serotypes Ia, II, and III were predominant. Compared with culture-negative women, the group of women colonized rectally had markedly elevated levels of both immunoglobulin A (IgA) and IgG antibodies to GBS in cervical secretions and also had a moderate but significant elevation of IgA antibodies in sera. Women colonized only in the cervix had increases of specific IgA and IgG antibodies in cervical secretions, but their serum antibody levels were not elevated. In cervical secretions, the increase in antibody levels in the groups of colonized women was most pronounced for the IgG isotype, indicating a mucosal immune response involving IgG as well as IgA. A close correlation was found among the levels of antibodies to each of the three GBS serotypes tested. Evidence for such cross-reacting antibodies to different serotypes of GBS, as well as to group A streptococci, was also obtained from absorption experiments. Altogether, our results show that undiluted secretions for antibody determination can be easily collected from the uterine cervix with absorbent wicks and demonstrate that colonization of GBS in the rectum and the uterine cervix may induce a systemic as well as a pronounced local immune response in the female genital tract. The findings may have implications for the development of a mucosal vaccine against GBS disease.

Adolescent↗
PubMed1993

A comparison of yield from cervix versus vagina for culturing Candida albicans and Trichomonas vaginalis.

OBJECTIVE: To determine the agreement of culture results of Candida albicans and Trichomonas vaginalis from the cervix versus posterior fornix in women with vaginal symptoms. DESIGN: Same patient comparison of culture results from two sample sites. SETTING: Twenty one general practices in Amsterdam and the east of the Netherlands. SUBJECTS: Six hundred and eighty two women aged 15 to 55 years with vaginal symptoms, seen between 1 October 1987 and 31 May 1990. MAIN OUTCOME MEASURES: For each site (cervix and posterior fornix) the proportion of detected C albicans and T vaginalis. The sensitivity of the cervical swab related to the vaginal one. The percentage of concordance for both microorganisms. RESULTS: In 248 (34%) women C albicans was diagnosed and in 38 (6%) T vaginalis. In 99% of the proven C albicans cases, the yeast was found in the vagina. In 94% C albicans was isolated from the cervix. Sensitivity of the cervical swab was 94%. In 98% of the patients a concordant observation was made regarding detection of yeast. In 97% of the proven T vaginalis cases the protozoon was found in the vagina. In 91% T vaginalis was detected from the cervical swab. Sensitivity of the cervical swab was 92%. The culture results were concordant in 99%. CONCLUSION: The yield from the vaginal source was slightly better than that from the cervix for culture of both microorganisms. For screening purposes, specimen-collection for culture of N gonorrhoeae, C albicans and T vaginalis can be combined in one swab taken from the cervix.

Adolescent↗
PubMed1989

Studies of the innervation of rabbit myometrium and cervix.

We characterized the innervation of isolated circular and longitudinal-oriented muscle strips from the nulliparous rabbit uterus and cervix by field stimulation (FS). FS with increasing frequency (2.5-50 pps) and voltage (2.5-70 V) caused graded increases in isometric contraction with no relaxation or inhibition of spontaneous activity. Tetrodotoxin (TTX, 3.1 X 10(-6) M) significantly reduced the FS response by 75% in all strips at higher stimulus frequencies. Contractile responses to FS were also significantly inhibited by atropine (3.5 X 10(-6) M) in circular uterus and in longitudinal cervix. Guanethidine (5 X 10(-6) M) reduced the response in all strips, as did phentolamine (3.6 X 10(-6) M) in longitudinal uterus and circular cervix. Propranolol (3.9 X 10(-6) M) did not significantly change the response in longitudinal uterus or circular cervix. In longitudinal uterus, combined guanethidine and atropine produced significant inhibition, but not statistically different from either drug alone. Similar results were seen in circular uterus. Electron microscopy and glyoxylic acid histofluorescence indicate that both blood vessels and smooth muscle in rabbit uterus are supplied with adrenergic nerves. The results suggest the presence of TTX-sensitive adrenergic and cholinergic excitatory innervation of rabbit uterus and cervix.

Adrenergic Fibers↗
PubMed1991

Hormonal control of the cervix in pregnant gilts. III. Relaxin's influence on cervical biochemical properties in ovariectomized hormone-treated pregnant gilts.

The effects of relaxin on the biochemical properties of both the uterine and vaginal portions of the cervix were examined between days 80-110 of pregnancy in ovariectomized gilts given progesterone to maintain pregnancy. In the cervix of control gilts and those ovariectomized and given progesterone plus relaxin, wet and dry weights, water content, and the glycosaminoglycan/collagen ratio increased between days 80-110 of gestation. Collagen concentrations based on wet or dry weight and glycosaminoglycan concentrations based on wet weight decreased during this period. After ovariectomy, there were no changes in these cervical connective tissue components when relaxin was not given. The glycosaminoglycans hyaluronic acid, heparan sulfate, and dermatan sulfate were found in the cervices of all treatment groups, with dermatan sulfate predominating. The ratio of the individual glycosaminoglycans did not change during pregnancy or with treatment. The major dermatan sulfate proteoglycan from the pig cervix was isolated and found to be similar in size, immunoreactivity, amino acid composition, and amino acid sequence to the major dermatan sulfate proteoglycans isolated from the cervices of other mammals. It is concluded that the relaxin-induced changes in the connective tissue composition of the cervix may contribute at least in part to increased extensibility and growth of the cervix during the last third of gestation in pigs.

Animals↗
PubMed1995

Immunohistochemical localization of specific relaxin-binding cells in the cervix, mammary glands, and nipples of pregnant rats.

Previously, we demonstrated that endogenous circulating relaxin promotes the growth and softening of the cervix, the development of the mammary glands, and the growth and development of nipples. Due to the remarkably similar modifications in the histological appearance of the extracellular matrix in the cervix, mammary glands, and nipples, we hypothesized that there may be a common mechanism(s) of action of relaxin in these tissues. A fundamental step toward understanding this mechanism is to identify specific cells that contain relaxin receptors, that is to identify those cells that initiate relaxin's effects within relaxin target tissues. To identify specific relaxin-binding cells in the cervix, mammary glands, and nipples of the pregnant rat, a biologically active biotinylated relaxin probe was prepared. This probe for putative relaxin receptors was administered to intact rats on day 18 of pregnancy. After 1 h, the animals were killed, and tissues were fixed by immersion in 4% paraformaldehyde for 10 h. Fixed tissues were rinsed in 0.1 M phosphate buffer (pH 7.4) and cryoprotected in an ascending series of 5%, 10%, and 20% sucrose solutions. The tissues were frozen in Tissue-Tek O.C.T. compound and stored at -70 C until sectioning. Frozen sections (12 microns) were cut on a Tissue Tek II cryostat at -24 C and thaw mounted on slides coated with 0.01% poly-l-lysine (mol wt, 300-6000). The biotinylated relaxin was localized in cryosections with an antibiotin immunoglobulin G conjugated to colloidal gold, which was subsequently visualized for light microscopy with silver intensification. Specific binding of the biotinylated relaxin was localized in the epithelial and smooth muscle cells of the cervix, the epithelial cells of the mammary glands, and the epithelial cells, smooth muscle cells, and skin of the nipples. We conclude that those cells exhibiting specific relaxin binding probably contain relaxin receptors and, therefore, mediate relaxin's effects in these tissues. As relaxin bound specifically to epithelial cells in the cervix, mammary glands, and nipples, we postulate that the epithelial cells may initiate a common mechanism of action that brings about modifications of the extracellular matrix in all three tissues.

Animals↗
PubMed1994

Characterization and localization of a putative oxytocin receptor in the cervix of the oestrous ewe.

The purpose of the present study was to investigate the presence of high-affinity oxytocin-binding sites (putative oxytocin receptors) in the cervix of the non-pregnant ewe. [3H]Oxytocin binding to the peripheral layers of cervical tissue (comprising the serosal layer and the least dense collagenous and muscular layers) and the remaining dense collagenous cervical tissue were studied separately. [3H]Oxytocin-binding sites were detected in membrane fractions prepared from both of these regions, but binding to the peripheral cervix was variable and binding site concentrations were low, hence these were not characterized further. A high-affinity oxytocin-binding site, having a dissociation constant of 1.8 nmol/l, was characterized in the dense collagenous regions of the cervix of ewes killed during the oestrous period. Similar dissociation constants were determined for [Arg8]-vasopressin and the oxytocin-specific agonist [Thr4, Gly7]-oxytocin in competition studies. [3H]Oxytocin binding to peripheral cervical tissue and to the dense collagenous cervix was generally low or undetectable during the luteal phase, but increased in both tissues around the time of luteolysis. Although specific binding to both tissues was variable during the oestrous period, it was higher at this time than during the luteal phase. [3H]Oxytocin-binding site concentrations were also found to be higher within the inner dense collagenous cervix of oestrous ewes than of pregnant, ovariectomized or anoestrous animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗