Search

We study a common-value bilateral bargaining model with equity offer. In particular, we consider a model in which players bargain over an equity share of a common-value stochastic pie (i.i.d. over time) and players receive private signals on the size of the pie each period. Efficient agreement is a stochastic rule: Delay is efficient if the expected size of today’s pie is small and the discount factor is high. Hence, information aggregation is crucial for efficiency. We derive the conditions under which an equilibrium that attains the efficient agreement exists. The key idea is that the proposer makes an offer in such a way that the responder will use her signal if the responder’s signal is crucial for an efficient agreement., ファイル公開：2019/03/01

We establish a model of market competition between large and small firms and investigate the way in which demand substitutability affects how the entry of big firms impacts incumbents. We focus on the relative strength of two opposing effects of entry on large incumbent firms’ demand: the direct substitution effect among large firms (negative) and the indirect feedback effect through the change in small firms’ aggregated behavior (positive). If the substitutability between large and small firms is sufficiently high, the indirect effect dominates the direct effect and large incumbents’ equilibrium prices and profits increase. We show that welfare effects are ambiguous, which calls for careful assessment when regulating large firms’ entry.

We study the dynamics of entry and exit based on firms' learning about their relative cost positions. Each firm's marginal cost of production is its own private information, thereby facing ex ante uncertainty about its cost position. The (inelastic) market demand can accommodate only a fraction of firms to operate, and thus only firms with relatively lower costs are viable in the long run. Some firms in the market will exit if excessive entry (or overshooting) occurs. We derive the unique symmetric sequential equilibrium. The equilibrium properties are consistent with empirical observations: (i) entry occurs gradually over time with lower cost firms entering earlier than higher cost firms, (ii) exiting firms are among the ones that entered later (indeed in the last period). Moreover, equilibrium overshooting probability is shown to always be positive and decreasing over time.

This note applies an evolutionary analysis to Skaperdas's (1992) static model of conflict and cooperation, in which agents are faced with trade-offs between joint production and share competition. We adopt the stochastic evolution approach, and assume that each agent occasionally mimics the action of the winner of the stage. In contrast to Skaperdas's results that justify full or partial cooperation in productive activity, the long-run equilibrium must exhibit total conflict; nobody engages in production at all.

We study an infinitely repeated Bertrand game in which an i.i.d. demand shock occurs in each period. Each firm receives a private signal about the demand shock at the beginning of each period. At the end of each period, all information but the private signals becomes public. We consider the optimal symmetric perfect public equilibrium (SPPE) mainly for patient firms. We show that price rigidity arises in the optimal SPPE if the accuracy of the private signals is low. We also study the implications of more firms and firms’ impatience on collusive pricing. Empirical evidence shows that prices in oligopolistic markets tend to be more rigid than prices in competitive markets (Dixon, 1983; Carlton, 1986). This suggests that collusion may result in firms’ inflexible pricing behavior. It is not obvious, however, that collusion causes price rigidity. Why do colluding firms not adjust prices according to changing environments, by which they can potentially earn higher profits? What limits colluding firms’ ability to coordinate, thereby leading to price rigidity? In this article, we study how information asymmetry among firms limits colluding firms’ ability to respond to demand shocks, and characterize the conditions under which prices are rigid. Specifically, we consider private information about demand in an infinitely repeated Bertrand game with two identical firms, in which an i.i.d. binary demand shock occurs in each period. Each firm receives a conditionally independent private signal about the underlying demand state at the beginning of each period, and then charges a price. The accuracy of private signals is measured by the probability of receiving a high (respectively, low) signal conditional on a high (respectively, low) underlying demand state. Therefore, the lower the accuracy, the higher the degree of informational asymmetry. At the end of each period, firms observe the underlying demand and the prices, but they never observe their rivals’ signals. We adopt symmetric perfect public equilibria (SPPE) as our solution concept, which requires that, at each period, firms’ pricing schemes

Background. The antitumor effect of indomethacin has been well documented in cancer patients and in animals with transplanted tumors. Indomethacin has also been regarded as a biological response modifier. Therefore, we presumed that indomethacin could be a modulator of antitumor agents, and this study was done to determine whether indomethacin modified the cytotoxicity of selected antitumor agents.

The antitumor effect of indomethacin on Colon 26, Meth-A and FM3A tumors was investigated in mice. The prostaglandin E2 content in tumor tissues was assayed to find out if indomethacin acts on tumors, and the telomerase activity in tumors and somatic tissues (testis, liver, spleen and colon) was also monitored during indomethacin treatment. Growth of Colon 26, Meth-A and FM3A tumors was significantly (P < 0.001-0.05) suppressed by indomethacin compared to the untreated controls. The prostaglandin E2 content in the three tumors was markedly (P < 0.001) reduced by indomethacin. Telomerase activity in Colon 26 and FM3A tumors was significantly (P < 0.001) lower than that of untreated tumors (80% and 45% decrease versus the controls, respectively), and the activity in Meth-A tumor was slightly decreased (10% decrease versus the control) by indomethacin. Telomerase activity in the somatic tissues was not significantly affected by indomethacin. In summary, this study shows the effectiveness of indomethacin as an antitumor agent against three types of tumors, and suggests that indomethacin affects telomerase activity in tumors in vivo.

The antitumor effect of indomethacin on Colon 26 tumor was investigated in conventional (CDF1) and nude mice (BALB/c nu/nu), and the telomerase activity in the tumor tissues treated with indomethacin was monitored. Growth of Colon 26 tumor was significantly suppressed with indomethacin treatment compared to the controls both in conventional and nude mice. And telomerase activity in the tumor tissues noticeably declined in contrast to normal somatic tissues (testis, liver and colon), which were not affected by indomethacin treatment. We also showed that indomethacin can suppress tumor growth in association with a preferential decrease in telomerase activity in tumor tissues both in conventional and nude mice to the same extent. This study suggests a method for investigating the mechanism of tumor suppression by indomethacin, and suggests that indomethacin might be useful as a novel agent for human cancer therapy.

UE8 is a uterine epithelial cell line established from p53-deficient fetal female mice. UE8 exhibits a typical epithelial morphology in culture and is strongly positive for cytokeratin, but negative for vimentin in immunocytochemistry. UE8 shows an active growth in a phenol red free 1:1 mixture of Dulbecco's modified Eagle's medium and Ham's nutrient mixture F-12 supplemented with 3% heat-inactivated and dextran-coated charcoal-treated fetal calf serum. Both immunocytochemistry and immunoblot analyses confirmed that UE8 was negative for the estrogen receptor. Diethylstilbestrol added to the medium at concentrations between 10−6 and 10−8 M had no significant effect on the proliferative rate, and estradiol-17β at 10−6 M was slightly inhibitory. Unexpectedly, however, the“pure anti-estrogen”ICI 182,780 at 10−6 M significantly enhanced cell proliferation. This is the first observation that the“pure anti-estrogen”ICI 182,780 stimulates the growth of uterine epithelial cells without estrogen receptors.

BACKGROUND We demonstrated that p53-deficiency is sufficient for immortalization of fetal uterine cells. In the present study, we further extended our previous observations to prostate tissues from a young p53-deficient adult mouse. METHODS Cell lines were established from the ventral prostate of a p53-deficient male mouse and maintained in medium containing 10% heat-inactivated fetal calf serum supplemented with insulin (10 μg/ml), transferrin (10 μg/ml), cholera toxin (10 ng/ml), and selenium (10−8 M). RESULTS Pro9ad, one of the lines established, exhibits a typical epithelial morphology in culture. Despite the possession of androgen receptors, the growth of Pro9ad was not stimulated by 5α-dihydrotestosterone. Hepatocyte growth factor (HGF) slightly stimulated proliferation, whereas fibroblast growth factor-1 (FGF-1), keratinocyte growth factor (KGF), and platelet-derived growth factor AB (PDGF-AB) had no stimulating effect on growth. However, FGF-2, epidermal growth factor (EGF), and insulin-like growth factor-1 (IGF-1) accelerated proliferation in a dose-dependent manner. EGF and IGF-1 additively stimulated growth. CONCLUSIONS These results suggest that Pro9ad shares characteristics in common with primary prostatic epithelial cells despite p53-deficiency, and that p53-deficiency alone allows establishment of clonal cell lines of the prostate epithelium. Furthermore, the prostates of p53-deficient mice are useful sources for obtaining cell lines. Prostate 36:102–109, 1998. © 1998 Wiley-Liss, Inc.

Background This study uses Colon 26-bearing CDF1 mice to assess the pharmacologic actions of indomethacin on tumor growth and cancer cachexia. The effect on tumor growth was evaluated by tumor weight, and the effect on cachexia was screened by changes in body weight and food intake. Additional indices measured included serum levels of immunosuppressive acidic protein and interleukin-6, and prostaglandin E2 content in the tumor tissues.

UE8 is one of several uterine cell lines established from p53-deficient fetal female mice. UE8 exhibits a typical epithelial morphology in culture; it is strongly positive for cytokeratin, but negative for vimentin. Immunoblot analysis confirmed that UE8 has glucocorticoid receptors. It grows actively in medium supplemented with 3% heat-inactivated, dextran-coated charcoal-treated fetal calf serum. Dexamethazone (DEX) inhibited its growth dose-dependently at concentrations between 10−6and 10−9 M. The inhibition by DEX was further examined in chemically defined medium (CDM): DMEM/F12 containing transferrin (10 μg/ml), selenium (10−8 M) and 0.1% bovine serum albumin. DEX at 10−6 M inhibited the growth of UE8 in CDM or in CDM supplemented with insulin-like growth factor-1 (IGF-1: 10 ng/ml), but there was no inhibition by DEX(10−6M) in the presence of epidermal growth factor (10 ng/ml). Thus, DEX inhibits the growth of a uterine epithelial cell line derived from p53-deficient mice in vitro, and also ...

A cDNA (1555 bp) (DNA database accession number, D61396) having a homology with human vitronectin (Vn) was isolated from a porcine liver cDNA library, and its sequence was determined. The open reading frame in the cDNA was found to code a protein with 388 amino acids, then the amino acid sequence of the protein (porcine putative Vn) was aligned to the other mammalian (mouse, rabbit, and human) Vns previously reported. The alignment revealed that the functional amino acid sequences reported as the cell attachment site, the heparin binding site, the region involved in glycosylation, and plasminogen activator inhibitor I-binding domain were conserved in the porcine putative Vn. These findings together with the fact that the calculated molecular weight and the N-terminal amino acid sequence of the putative Vn agreed with those reported by biochemical analysis on porcine Vn, led us to conclude that the cDNA isolated in the present study coded for the porcine Vn. Then, a time course study was performed to examine whether the administration of growth hormone (GH) affects Vn mRNA expression in liver and skeletal muscle, since the level of Vn mRNA was reported to be affected by inflammation, and since GH was reported to be involved in inflammation. This revealed that GH has no effect on the level of liver Vn mRNA, and that Vn mRNA level in skeletal muscle seemed to be affected following GH-injection.

We offer a general framework to study procurement auctions when quality matters. In this environment, sellers compete for a project by bidding a price-quality pair, and the winning bidder is determined by the score assigned to each bid. In contrast to the existing study in which only the quasilinear scoring rule is considered, our analysis allows a broad class of scoring rules including many other realistic ones. We focus on the analyses of the equilibrium bidding behavior of first-score (FS) and second-score (SS) auctions. We find that FS or SS auctions can be transformed into equivalent, single-dimensional score-bid auctions where the bidder's utility (payoff upon winning) is non-linear in the score-bid. Our analysis demonstrates that the ranking of the two auction formats, in terms of expected scores, depends on the scoring rule and that the equivalence fails unless scoring rules are quasilinear. FS auctions induce less aggressive bidding than SS auctions if, for example, the scoring rule is price-quality ratio (PQR).

Among the chicken breeds, White Leghorn (WL) and White Plymouth Rock (WR) are major breeds and have different history in their establishments. Whole mitochondrial DNA of the breeds were sequenced in order to elucidate the genetic relationship between the breeds. The lengths of the two WL and two WR mitochondrial DNA were found to be 16 788 and 16 785 base pairs, respectively. When the DNA sequences were compared, the similarity was found to be 99.96% (six nucleotide differences). In addition, the present study conformed the existence of an extra nucleotide ‘C’ in NADH dehydrogenase subunit 3 (ND3) of the chicken mitochondrial DNA, which has been consistently observed in Galliformes.

This study investigates the primary effect of the eye lens obsolescence (Elo) gene of the mouse. Morphological features of the Elo lens were defined as follows: (1) deficient elongation of lens fiber cells, (2) morphological abnormality of nuclei of lens fiber cells, (3) lack of eosinophilic granules in the central fiber cells and (4) rupture of lens capsule in the posterior region. We have immunohistologically examined, by means of an in vivo BrdU incorporation system, whether or not the Elo gene regulates cell proliferation during lens development. The lens fiber cells were morphologically abnormal in day 13 embryonic Elo lens. However, there were no significant differences in morphology or cell proliferation between normal and Elo lens epithelium until day 14 of gestation. After day 15, the total cell number in the Elo lens epithelium was significantly less than that in the normal, but the total numbers of S-phase cells in the two genotypes were not significantly different. The ratio of the total S-phase cell number to the total number of lens epithelial cells may be affected by the developmental stage, but not directly by the genotype. The genotype, however, may be having a direct influence at later ages because malformation of Elo lens fiber cells must cause reduction of the total number of lens epithelial cells in older embryos. Although, at 30 days old, Elo lens cells were externally extruded through the ruptured capsule into the vitreous cavity, BrdU-labelled lens epithelial cells were detectable. To investigate whether the Elo lens phenotype is determined by its own genotype or by its cellular environment, we produced aggregation chimeras between C3H-Elo/+(C/C) and BALB/c (c/c). Most lenses of BALB/c dominant chimeras were oval in shape without the ruptured lens capsule. However, they were opaque in the center and slightly smaller in size than normal. The lenses of C3H-E/o/ + dominant chimeras were morphologically similar to the Elo lens. Although normal nuclei were regularly arranged in the anterior region, Elo-type nuclei were located in the posterior region. Immunohistological staining by using anti-C3H strain-specific antibody demonstrated that the lens fiber cells with abnormal nuclei were derived only from C3H-Elo/+, not from BALB/c. These observations suggest that the primary effect of the Elo gene in the developing lens may be specific to the fiber cell differentiation rather than to the cell proliferation. Moreover, the Elo gene may be autonomously expressed in the differentiating lens fiber cells, and intracellularly inhibit fiber cell elongation.

Completely everted uterine horns of proestrous mice were treated with trypsin at 4°C and with a minimum mechanical agitation, and their surface epithelia were separated from the stroma and uterine glands with a minimum contamination of non-epithelial cells. The epithelial cell fraction was further purified by collagenase-dispase treatment, Percoll gradient separation and short term cultures on the collagen gel (5 min×3). Immunocytochemical check of cytokeratin networks in the cytoplasm proved well the purity of the cell fraction finally obtained.The epithelial cells could proliferate well in the medium composed of a 1:1 mixture of Ham's F12 and Dulbecco's modified Eagle medium containing 50 μM of Ca2+ and supplemented with epidermal growth factor (EGF), insulin, transferrin, bovine serum albumin (BSA), vitamin A and hydrocortisone, when seeded on the collagen gel at a density higher than 2×105/well (ca. 1, 000 cells/mm2). Deletion of anyone of insulin, transferrin and BSA from the culture medium suppressed severely the cell proliferation, while an only partial suppression was caused by the omission of EGF. Either single or simultaneous removal of vitamin A and hydrocortisone did not affect the proliferation at all. No stimulating effect of estradiol-17β on the proliferation was observed.

To apply the bromodeoxyuridine (BrdU) labeling method using a monoclonal antibody to the study of cell proliferation in the mouse uterus, methods of fixation and embedding of tissues and of immunofluorescent staining were compared in terms of the rate of detection of labeled cells and specificity and stability of fluorescence obtained. BrdU was administered intravenously 2 hr before death and uterine blocks were embedded in polyester wax and Technovit resin after fixation in formalin and periodate-lysine-paraformaldehyde, respectively. The indirect method with anti-BrdU and fluorescein isothiocyanate (FITC) conjugated antimouse IgG antisera and the direct method with FITC conjugated anti-BrdU antibody were applied to both wax- and resin-embedded sections. Labeled and total cells were counted in luminal and glandular epithelia and stomata adjoining them. Counterstaining with hematoxylin for counting total cells produced intense fluorescence over the whole of resin sections and made counting of labeled cells impossible. On wax sections, on the other hand, the results were satisfactory, although the number of labeled cells detected was decreased slightly. In wax sections fluorescence due to nuclear incorporation of BrdU in the indirect method could be easily distinguished from the cytoplasmic or extracellular emission seen in some cells by its location and characteristic color. In resin sections, however, more careful observation was needed since the second antibody used in the indirect method cross-reacted with IgG in eosinophils and produced cytoplasmic fluorescence of the same color. By the indirect method greater numbers of labeled cells were detected in wax sections than in resin sections. The difference was distinct in tissues with extensive cell proliferation. By the direct method the fluorescence obtained was weaker and apt to fade more quickly than that obtained by the indirect method; use of the direct method reduced the number of labeled cells detected in both wax- and resin-embedded sections.

A holdup model is analyzed in which one party, the seller, has an investment project that the other party, the buyer, can subsidize. The investment project remains the seller's; she cannot transfer her entire control rights to it. In particular, she can always refuse to allow the buyer to subsidize her investment if the subsidy would put the buyer in too strong a bargaining position ex post. Even with the subsidization opportunity, the holdup inefficiency is still present, except in the special cases in which one party has all the bargaining power. The adoption of a contract, however, allows full efficiency to be achieved more generally. In particular, if the seller's investment project imposes a positive externality on the buyer but does not reduce her own production costs, a buyer's option contract exists that achieves full efficiency. This is in contrast to the result of Che and Hausch (1999) that without a subsidization opportunity, contracting has no value in this "purely cooperative" case. If the investment lowers the seller's costs as well as raises the buyer's value, whether full efficiency can be achieved depends on how cooperative the investment is. Full efficiency can be achieved if the cooperativeness of the investment is either sufficiently high or sufficiently low

Clonal cell lines have been established from vaginae of prepubertal female p53-/- mice. Because the mouse vagina has a dual origin (the cranial three-fifths derived from the Mullerian duct and the caudal two-fifths derived from the urogenital sinus), both parts were separately subjected to cloning. Sixteen epithelial and two fibroblastic cell lines established from the cranial three-fifths (Mullerian vagina group), and four epithelial and three fibroblastic cell lines were established from the caudal two-fifths (sinus vagina group). They were maintained in Dulbecco's modified Eagle medium and Ham's nutrient mixture F-12 containing 10% fetal calf serum and 17β-estradiol at 10−8 M. Two cell lines (one epithelial and one fibroblastic) were examined using soft agar assay, but no colonies were formed. The doubling time of cell lines was approaximately 24 h, and all of them divided more than 200 times without crisis, suggesting that they were immortalized. All epithelial cell lines expressed cytokeratin 8. However, the epithelial cell lines expressed cytokeratin 14 and cytokeratin 10 when exposed to medium containing different concentrations of Ca2+. Fibroblastic cell lines expressed vimentin. All epithelial and fibroblastic cell lines expressed estrogen receptor-α protein. This is the first successful establishment of clonal cell lines from the normal mouse vagina, and these lines may provide good models in vitro of the vagina for the study of the mechanism of estrogen action.

Background We demonstrated that p53-deficiency is sufficient for the establishment of clonal cell lines from the uterus and prostate. In the present study, we improved cloning methods to establish androgen-responsive cell lines. Methods In our previous study, a prostatic cell line was established from the ventral prostate of a p53-deficient mouse and was maintained in a medium containing heat-inactivated fetal calf serum at 10% supplemented with insulin (10 μg/ml), transferrin (10 μg/ml), cholera toxin (10 ng/ml) and selenium (10−8 M). In the present study, 5α-dihydrotestosterone (10−8 M) was added to the medium from the beginning of cloning procedures. Results We succeeded in the establishment of an androgen receptor positive prostatic cell line, designated PEA5. PEA5 cells exhibited a typical epithelial morphology in culture and growth was stimulated by androgens in a dose-dependent manner. In addition, they grew and formed three-dimensional structures in collagen gel, in which growth was also stimulated by androgen. Conclusions Although PEA5 lacks p53 gene, it still retains androgen sensitivity. In collagen gel culture, PEA5 cells can grow and form three-dimensional structures similar to those of the primary cultures reported previously. Furthermore, prostates of p53-deficient mice are shown to be useful sources for obtaining androgen-responsive cells lines. Prostate 46:214–225, 2001. © 2001 Wiley-Liss, Inc.

Cervicovaginal secretions (CVSs) contain cytokines of maternal origin (1)(2), inflammatory cells, and proteolytic enzymes derived from leukocytes (3)(4) and act to protect the intraamniotic compartment from infectious agents that may ascend along the birth canal. CVSs have been found to contain ceruloplasmin (Cp) (5), a protein formed predominantly in the liver. The potential functions of Cp have been divided into two categories: (a) transportation of copper to tissue sites, and (b) functions such as oxidase activity of aromatic amines and serum antioxidation. In this setting, Cp acts as an extracellular scavenger of free radicals and superoxide ions and endogenously modulates inflammatory responses (6). The former function uses inactive Cp, and the latter function is carried out by active Cp. Hiyamuta et al. (7), using an original ELISA method that they established, found both inactive and active Cp in human serum. In a preliminary screening, active Cp was shown to be present in several external body secretions, such as in tears, salivary excretions, and nasal discharge. In this study, we used this assay system to measure active Cp in CVS in term pregnancy, and we found that increased active Cp in CVS was associated with premature rupture of the membranes (PROM). We enrolled 80 women at term pregnancy. With an informed consent from these 80 women, CVS was obtained from the cervical canal at ∼36 weeks of pregnancy, using a pair of sterilized cotton swabs (Japan Medical Service) at the time of regular antepartum checking. The total volume of collected CVS was weighed, and the mean CVS collected was ∼20 mg. One of the paired sterilized cotton swabs was used routinely for microbial culture. The other sterilized cotton swab was transferred to a silicon-coated polypropylene tube containing phosphate-buffered saline (1.0 mL) and rinsed vigorously. These samples were …

Our aim was to examine the changes in spatiotemporal tenascin (TN) expression in mouse uterus during early pregnancy, when the uterine tissue undergoes a tremendous restructuring.Using immunohistochemistry and in situ hybridization, the changes in distribution of TN protein in mouse uterine tissues in pregnancy Day 0 through Day 5 were analyzed.Immunoreactive TN and TN mRNA were expressed in the basement membrane of the epithelium as well as in the smooth muscle layer, and their distribution shifted from the subbasement region on Day 0-3 to the smooth muscle layer on Days 4 and 5.These results indicate that TN expression in the uterus during early pregnancy is spatiotemporally different and may be regulated by a different mechanism.

Oviductal functions have been studied mainly in primary epithelial cell culture and organ culture. However, secretory cells and ciliated cells coexist in the epithelium, and the small size of the oviduct limits the sources of both epithelial and stromal cells. To circumvent the limits, we attempted to establish clonal cell lines from an oviduct of a p53-deficient mouse. An oviduct was enzymatically digested and cultured in medium containing 10% fetal calf serum supplemented with estradiol-17beta. Morphologically distinct clones (10 epithelial and 4 fibroblastic clones) were established, and all clones expressed estrogen receptor alpha and progesterone receptor. Expression of a mouse oviduct-specific glycoprotein gene as a marker of secretory cells was limited in one clone and was stimulated by estrogens and suppressed by progesterone. Expression of helix factor hepatocyte nuclear factor/forkhead homologue-4 gene as a marker of ciliated cells was limited in two clones and was suppressed by estrogens. The two genes were never coexpressed in any clones. The results strongly suggest that the oviductal epithelium consists of two functionally determined populations. To our knowledge, this is the first establishment of functional clonal cell lines of the oviduct and makes it possible to study independently two oviductal functions, secretion and ciliogenesis.

To confirm the utility of the bromodeoxyuridine (BrdU) labeling method in the study of cell proliferation in mouse uterine tissues, changes in the labeling index in the luminal and glandular epithelia, the periluminal, periglandular and deep stromal regions and the myometrium were surveyed in normal adult mice during the estrous cycle and early pregnancy, in prepubertal mice and in ovariectomized adult and young animals treated with estrogen and/or progesterone. All results obtained were consistent with those obtained in previous histometric and autoradiographic studies and proved the effectiveness of the BrdU labeling method in the study of the uterus as well as many other organs. A marked rise in the labeling index was found in the luminal epithelium at metestrus, as well as on the proestrous morning, indicating the occurrence of extensive cell proliferation in the absence of estrogen stimulation. The change in the labeling index in adult mice was much more evident in the luminal epithelium than in the glandular epithelium in all conditions examined. On the other hand, the change in the stroma was more eminent in the periglandular region than in the periluminal and deep regions in most conditions. In immature mice, a great increase in labeling incidence occurred not only in luminal epithelium but also in muscle layers along with the process of puberty and at the time of estrogen stimulation. A moderate increase in the incidence also occurred in all other areas of the uterus including the perimetrium. Again, the increase was more prominent in the periglandular area than in other stromal regions.