Ovarian mucinous cystadenoma with smooth muscle proliferation in a cynomolgus monkey (Macaca fascicularis)

An ovarian mucinous cystadenoma was found in a 5-year-old female cynomolgus monkey (Macaca fascicularis). The tumor was composed of various sizes of multilocular cystic glands lined by a single layer of mucin-filled epithelium. Each of these cystic glands was surrounded by a large amount of solid fibrous stroma resembling smooth muscle. The ovarian surface epithelium showed partial invagination into the ovarian cortex, and a transition was observed between the surface epithelium and the mucinous cyst-forming epithelium. Immunohistochemically, the stromal cells were positive for alpha-smooth muscle actin and proliferating cell nuclear antigen. Ultrastructurally, the glandular epithelium had numerous mucinous secretory granules and microvilli. The stromal cells had numerous parallel microfibrils with focal density. It is rare to encounter evidence of a transition from the surface epithelium to the mucinous tumor epithelium and to show stromal smooth muscle proliferation in a mucinous cystadenoma.     

Histopathologic and Immunohistochemical Exam in One Case of Canine Endometrial Adenocarcinoma

Canine endometrial carcinomas are rare, and mostly occur in geriatric bitches. In this work, the uterus of a 10‐year‐old female Boxer evidencing an endometrial carcinoma on the body of the uterus was used to describe the histopathological features of the tumour and to study its immunophenotype. In this work, a panel of immunomarkers (cytokeratins AE1/AE3 and 14, vimentin, CD10 and Ki‐67) was applied to the endometrial carcinoma to establish the staining patterns indicative of the tumour agressiveness and cellular differentiation. Additionally DNA ploidy was also performed. In this case, the tumour showed papillar pattern, with large pleomorphic, anaplastic cells and also some aberrant multinucleated and giant cells. In some areas of the tumour, it was also observed cytotrophoblastic‐like cells outlining the papillae. Cytokeratin AE1/AE3 expression was detected in the luminal neoplasic cells. Cytokeratin 14 positivity was sporadic and irregular, and was observed mainly in the luminal epithelium. Only stromal and aberrant cells showed a positive staining to vimentin. Positive membranous staining to CD10 was evidenced by clear epithelial, cytotrophoblastic‐like cells at the tumour surface but not by the stromal cells. The mitotic and Ki‐67 indices were low, suggestive of a weak aggressiveness of the tumour. The multinucleated and giant cells evidenced a positive immunostaining to CK AE1/AE3, and CD 10; its positivity to vimentin was sporadic. This study aims to contribute to the advancement of the knowledge in canine endometrial carcinoma immunophenotype.     

发情周期不同阶段牦牛子宫中黄体生成素受体的表达变化

为研究发情周期不同阶段牦牛子宫中黄体生成索受体(LHR)的定位及表达变化,笔者利用免疫组织化学SP法分别检测发情期、发情后期、间情期和发情前期牦牛子宫中LHR的表达,并进行光密度值分析.结果表明,LHR免疫阳性产物在牦牛子宫腺上皮细胞、基质细胞、血管内皮细胞、血管平滑肌细胞和肌层平滑肌细胞中均有表达;腺上皮细胞、基质细胞和肌层平滑肌细胞中LHR在发情前期和发情期表达最弱,发情后期表达增加,间情期表达最强(P＜0.05);子宫内膜血管平滑肌细胞中LHR的表达在发情期最强,间情期最弱(P＜0.05);血管内皮中LHR在发情期和发情前期表达很强,发情后期和间情期显著下降(P＜0.05).结果表明LHR参与了发情周期不同阶段牦牛子宫功能变化的调控.     

Steroid receptor expression and HER-2/neu (c-erbB-2) oncoprotein in the uterus of cats with cystic endometrial hyperplasia-pyometra complex

The presence of oestrogen-alpha receptor (ER), progesterone receptor (PR), and HER-2/neu (c-erbB-2) oncoprotein in the uterine walls of 10 healthy cats and 20 subjects with cystic endometrial hyperplasia-pyometra (CEH-P) were evaluated. Lesions were graded according to the severity of cystic dilation, hyperplasia and inflammation, and were classified as normal, mild uterine hyperplasia and severe uterine hyperplasia. The ER, PR and c-erbB-2 expression in the endometrium, glandular epithelium, stromal fibroblasts and myometrial smooth muscle cells was quantified by immunohistochemistry. The ER, PR and c-erbB-2 staining patterns differed between normal uteri and uteri with CEH-P. The ER expression was tended to be higher in the endometrial surface and glandular epithelium in the severe hyperplasia group (P > 0.05) and significantly lower in the mild hyperplasia cases compared with normal endometrium (P < 0.05), whereas the PR expression in both severe and mild hyperplasia cases tended to be higher in stromal cells and glandular epithelium than those in the normal uteri. C-erbB-2 immunoreactivity was observed only in the endometrial surface and glandular epithelium of the uterine wall and immunostaining was found to be highest in cases with severe hyperplasia. As a conclusion, we suggest that c-erbB-2 oncoprotein may play a role in the pathogenesis of the CEH together with the ER and PR in cats, and that ER does not have a role in the mechanism of pyometra, whereas PR plays a role in the pathogenesis of both CEH and pyometra.     

Histological and Immunohistochemical Evaluation of Canine Ovary

In the present study, 15 canine ovaries without morphological lesions were examined histologically and immunohistochemically by using a large number of proteins including AE1/AE3, cytokeratin7 (CK7), CK13, CK20, vimentin, desmin, alpha smooth muscle actin (alphaSMA), calponin, S100, Neurofilaments, Inhibinalpha, placental alkaline phosphatase (PLAP) and neuron-specific enolase. Ovarian structures observed in this study included surface epithelium (SE), cortical tubules (CT), tunica albuginea (TA), stromal cells (SC), internal endocrine cells (IE), rete ovarii (RO) and fallopian tubes (FT). SE, CT, RO and FT were broadly immunoreactive for desmin. Besides AE1/AE3 and vimentin, desmin was also closely linked to these structures. Rete ovarii forming a reticular structure showed a positive reaction to S100. Surface epithelium was immunoreactive for PLAP at a significantly high level. In conclusion, these results indicate a specific segment of immunoreactivity as well as the broad range of immunoreactivity in canine ovary. The distinct patterns of immunoreactive for various kinds of proteins will play an important role in facilitating their identification and discrimination even in a normal canine ovary with a complex structure.     

Mixed apocrine sweat gland tumor of the tail in a cow

A 4-year-old native-breed cow had a mass with wide areas of ulceration and hemorrhage at the base of the tail at the same level as the vulva. The tumor was 19 X 13 X 11 cm, appeared red-brown, and was firm to hard, with gritty areas apparent on cut surface. Histologically, the tumor mass was composed of multilayered epithelial cells forming glandular structures with occasional apical blebs and rare solidly packed cells in nests. The stroma included fibrous connective tissue, scattered or periglandular sheets of spindle-shaped cells resembling myoepithelium, several cartilaginous formations, and numerous irregular islands of mineralized osteoid, well-formed bone trabeculae lined by osteoblasts, and many osteoclast-like multinucleated giant cells among or near the neoplastic epithelium. Immunohistochemically, the neoplastic epithelium was positive for pan-cytokeratin (AE1/AE2) and cytokeratin 19 but was negative for cytokeratin 18. Spindle-shaped cells were stained with alpha smooth muscle actin (alphaSMA) and to a lesser extent vimentin antibodies. The cells of osteogenic lineage and spindle cells closely associated with the osteoid showed strong immunostaining for vimentin but not for alphaSMA. Immunostaining for neuron-specific enolase and S100 protein was not observed in any component of the tumor mass. These findings suggested that the origin of bone formation was undifferentiated mesenchymal cells with osteogenic potential.     

Gastric stromal tumors in two rhesus macaques (Macaca mulatta)

Two female rhesus monkeys (Macaca mulatta, 10 and 24 years old) developed microcytic anemia and became terminally ill. At necropsy, large gastric masses were present, and, in one case, there were widespread abdominal metastases. Except for slightly atypical patterns, at the light microscopic level, the lesions resembled smooth muscle tumors. Ultrastructurally, however, cells in both tumors resembled primitive mesenchyme, while in one of the tumors, there were some characteristics of Schwann cells. No ultrastructural features of smooth muscle were present in either tumor. Vimentin and S-100 were detected immunohistochemically in both tumors. S-100 staining was more intense in the tumor with ultrastructural features of Schwann cells. Actin and desmin were not expressed in either gastric tumor, but diffusely stained a uterine tumor that was concomitantly present in one of the rhesus monkeys. The uterine tumor also exhibited typical ultrastructural features of smooth muscle. In the past, gastrointestinal stromal tumors in all species were thought to be of smooth muscle origin. Recently in human pathology, this conventional viewpoint has given way to the realization that there is a spectrum of neural crest and mesenchymal tumors. We report two gastric stromal tumors in two rhesus monkeys that histologically resembled smooth muscle tumors but were of neuroectodermal and primitive mesenchymal origin.     

Effects of nitric oxide and tumor necrosis factor-alpha on production of prostaglandin F2alpha and E2 in bovine endometrial cells

The purpose of this study was to determine whether nitric oxide (NO) mediates tumor necrosis factor (TNF)alpha influence on the bovine endometrium. TNFalpha influence on the bovine endometrium is limited to the stromal cells. Therefore, it was interesting to find out whether NO production by the stromal cells, stimulated by TNFalpha might influence the endometrial epithelium. Moreover, we investigated the intracellular mechanisms of TNFalpha- and NO-regulated prostaglandin (PG) F(2alpha) and PGE(2) synthesis. Epithelial and stromal cells from the bovine endometrium (Days 2-5 of the oestrous cycle) were separated by means of enzymatic dispersion and cultured for 6-7 days in 48-well plates. The confluent endometrial cells were exposed to a NO donor (S-NAP; 1-1000 microM) for 24 h. S-NAP strongly stimulated PGE(2) production in both bovine endometrial cell types (P<0.001). The effect of SNAP on PGF(2alpha) production was limited only to the stromal cells (P<0.05). To study the intracellular mechanisms of TNFalpha and NO action, stromal cells were incubated for 24 h with TNFalpha or S-NAP and with NO synthase (NOS) inhibitor (L-NAME; 10 microM) or an inhibitor of phosphodiesterase (IBMX; 10 microM). When the cells were exposed to TNFalpha in combination with NOS inhibitor (L-NAME), TNFalpha-stimulated PGs production was reduced (P<0.05). The inhibition of enzymatic degradation of cGMP by IBMX augmented the actions of S-NAP and TNFalpha on PGs production (P<0.05). The overall results suggest that TNFalpha augments PGs production by bovine endometrial stromal cells partially via induction of NOS with subsequent stimulation of NO-cGMP formation. NO also stimulates PGE(2) production in epithelial cells.     

Smooth Muscle Cells of the Bovine Cervical Stroma may have a Secretory, rather than a Contractile Function during Parturition

The bovine cervix contains a large amount of smooth muscle cells distributed over an outer muscular layer and within a stromal layer. The stromal layer exhibits no electromyographic (EMG) activity at parturition. This leads to the question whether the stromal smooth muscle cells of the bovine cervix are prepared to contract with parturition, or whether they have another function. To this end, cervical biopsies were repeatedly taken from 10 pregnant cows at day-185 and -275 of gestation, at spontaneous, uncomplicated calving and at 30 days after calving. The smooth muscle bundles of the stroma were immunohistochemically analysed (n = 5) with regard to their integrity and cellular density, and the degree of staining for connexin-43, smooth muscle actin α (SMA), desmin and vimentin. Additionally, the mRNA expression for connexin-43, SMA, desmin and vimentin was determined with RT-PCR (n = 5). The smooth muscle tissue was arranged in bundles, also at parturition. However, the cellular density of these bundles and the SMA mRNA expression were decreased at parturition. Additionally, the SMA staining and connexin-43 expression and staining remained constant during pregnancy and at parturition. This might indicate that stromal smooth muscle cells are not prepared to contract with parturition, in contrast to the myometrial smooth muscle cells. The smooth muscle cells, stained for SMA, also expressed vimentin, and the proportion of co-expression was increased at day-275 of pregnancy. This suggests that the stromal smooth muscle cells predominantly have a secretory function in cows.     

Infertility associated with the absence of endometrial progesterone receptors in a bitch

A three‐year‐old intact female Old English sheepdog was presented for evaluation of infertility. A uterine biopsy was performed during dioestrus, and the microscopic appearance was inconsistent with progesterone stimulation; the glands were sparse, simple and failed to show coiling, while the glandular epithelium was cuboidal instead of columnar. There was very little evidence of glandular activity. Due to the inappropriate appearance of the glands for the stage of the cycle, immunohistochemistry for progesterone receptors was performed. No progesterone receptor‐positive immunoreactivity was identified in the endometrial luminal epithelium, glandular epithelium or stroma. Weak intranuclear immunoreactivity was identified within the smooth muscle cells of the myometrium. The absence of progesterone receptors within the endometrial glands is the most likely explanation for the abnormal appearance of the endometrium and for this bitch's infertility. To our knowledge, this is the first report of endometrial progesterone receptor absence in a bitch.     

Immunohistochemical Localization of the Progesterone and Oestrogen α Receptors in the Uterine Horns of the African Giant Rat (Cricetomys gambianus)

The present study investigated the immunolocalization of the progesterone and oestrogen α receptors in the uterine horns of the African giant rat during the oestrous cycle. The progesterone and oestrogen α receptors were demonstrated in various cellular constituents of the endometrium, myometrium and perimetrium. The intensity of progesterone and oestrogen α receptor immunostaining in the endometrial and myometrial layers of the uterine horns varied during the oestrous cycle. The intensity of oestrogen α receptor immunoreactivity in the luminal epithelium was high during pro‐oestrus, oestrus and dioestrus. Progesterone and oestrogen α receptor immunoreactivity in the endometrial epithelia was absent during metoestrus. Moderate to strong immunostaining for the progesterone and oestrogen α receptors was demonstrated in the myometrial smooth muscle cells during pro‐oestrus, oestrus and dioestrus. The intensity of progesterone and oestrogen α receptor immunostaining in the myometrial smooth muscle cells was low during metoestrus. Stromal cells in the perimetrium consistently expressed progesterone and oestrogen α receptor immunoreactivity throughout the oestrous cycle. The findings of the study indicate that in the giant rat the immunolocalization of the progesterone and oestrogen α receptors, in endometrial and myometrial regions of the uterine horns, varies during the oestrous cycle.     

Epithelial-stromal tumor of the seminal vesicles in the transgenic adenocarcinoma mouse prostate model

The transgenic adenocarcinoma mouse prostate (TRAMP) model, designed for researching human prostatic cancer, was genetically engineered to harbor a transgene composed of the simian virus 40 Large-T/small-t antigen promoted by the rat probasin gene. In addition to prostatic neoplasms, the TRAMP mouse develops tumors in the seminal vesicles. This study was conducted to evaluate the pathology and histogenesis of TRAMP seminal vesicle neoplasms. Tissues of accessory sex organs harvested from 72 TRAMP mice of various ages (11-40 weeks of age) were fixed in neutral buffered formalin and stained with hematoxylin and eosin, desmin, 5-bromo-2'-deoxyuridine (BrdU, treated animals only), and SV40 Large-T antigen (SV40-Tag). In the seminal vesicles, we found neoplastic stromal cells that emerged multicentrically just beneath the epithelium, densely packed between the epithelium and the smooth muscle layer. These stromal cells frequently exhibited mitotic figures and showed BrdU incorporation and SV40-Tag protein expression in the nuclei and immunopositivity for desmin. The proliferative mesenchymal cells were lined by cuboidal to columnar epithelium. Some of the larger papillary, polypoid lesions exhibited a phyllodes pattern resembling that seen in mixed epithelial-stromal tumors of the breast, prostate, and seminal vesicles of humans. Although the epithelium was negative for SV40-Tag and showed only occasional incorporation of BrdU, it clearly participated in the biphasic proliferation, forming papillary, cystic, and tubuloglandular structures. No conclusive evidence of malignancy (invasion or metastasis) was identified. Our recommended diagnosis of this lesion in the seminal vesicles is epithelial-stromal tumor.     

Subcutaneous neoplasms of the ventral abdomen with features of adrenocortical tumors in two ferrets

A ventral abdominal subcutaneous mass was removed from each of 2 young adult spayed female ferrets. In both cases, the neoplasms were composed of islands of polygonal cells separated by interlacing streams of spindloid cells reminiscent of ferret adrenocortical tumors with smooth muscle proliferation. Immunohistochemically, the polygonal cells demonstrated strong cytoplasmic reactivity for inhibin and weak cytoplasmic reactivity for pancytokeratin and S-100 protein. Spindloid cells demonstrated strong cytoplasmic reactivity for alpha smooth muscle actin, muscle-specific actin, desmin, and glial fibrillary acidic [corrected] protein. Ultrastructurally, the polygonal cells contained numerous intracytoplasmic clear vacuoles, mitochondria, scant rough endoplasmic reticulum, and few intermediate filaments. In one tumor, vesicular tubular mitochondria were found in polygonal cells. The spindloid cells contained numerous aggregates of parallel intermediate filaments. The histologic, immunohistochemical, and ultrastructural findings are suggestive of adrenocortical tumors with smooth muscle proliferation, but cannot be differentiated from an ovarian gonadal stromal tumor. Neither ferret had a clinically detected primary adrenal gland tumor or clinical signs of adrenal-associated endocrinopathy.     

Intramedullary hemangioblastoma in a dog

A 6-year-old male Pointer dog was presented with a 4-week history of progressive hind-limb stiffness. Magnetic resonance imaging demonstrated a focal intramedullary lesion at T1 level with a pattern of ring contrast enhancement. At necropsy, a circumscribed intramedullary reddish-gray tumor was observed. Microscopically, the tumor was composed of thin-walled capillaries lined by endothelial cells and separated by pleomorphic cells (stromal cells) with a moderate degree of anisokaryosis. Immunohistochemically, the endothelial cells were positive for factor VIII-related antigen and the stromal cells were positive for neuron-specific enolase and vimentin. GFAP-positive astrocytes were occasionally observed within the tumor. Both endothelial and stromal cells were negative for synaptophysin, S-100 protein, pankeratin, smooth muscle actin, CD34, CD68, alpha1-antichymotrypsin, and lysozyme. The tumor showed considerable morphologic and immunohistochemical similarities with human hemangioblastoma, and hence the inclusion of this tumor type within the primary neoplasms of the canine central nervous system is suggested.     

Physiological and pathological expression of intermediate filaments in the equine endometrium

The aim of this study was to investigate the expression of the intermediate filaments cytokeratin, vimentin and desmin in the equine endometrium by immunohistological techniques. For this purpose, endometrial biopsies of 151 mares were examined to determine physiological cycle patterns and changes resulting from endometriosis. During the physiological cycle epithelial cells and mesenchymal cells express cytokeratin and vimentin, respectively, whilst desmin and vimentin were coexpressed by the smooth muscle cells. Epithelial coexpression of cytokeratin and vimentin was seen in numerous fibrotic glands and in the uterine glands of three mares with pathologically inactive endometria. Three different staining patterns (basal, perinuclear, diffuse) of vimentin were associated with typical morphological alterations of the affected epithelia. In addition, in 14 cases a stromal coexpression of vimentin and desmin was found, indicating an atypical stromal differentiation in inactive endometria of older mares, barren for several years.     

Insulin-like growth factor-I stimulated DNA replication in mouse endometrial stromal cells

Much evidence has suggested that sex steroid hormone-induced growth of uterine cells is mediated by polypeptide growth factors synthesized in uterine tissues. The present study aimed to clarify the effect of insulin-like growth factor-I (IGF-I) on the proliferation of mouse endometrial stromal cells obtained from immature mice. IGF-I and IGF-I receptor (type I) mRNAs were detected in the endometrial stromal cells. IGF-I increased bromodeoxyuridine (BrdU) uptake in the endometrial stromal cells, indicating an increase in DNA replication. E2 increased IGF-I mRNA levels in the endometrial stromal cells. IGF-I receptor is a tyrosine kinase receptor, and treatment with genistein, a tyrosine kinase inhibitor, reduced IGF-I-induced BrdU-uptake in the endometrial stromal cells. IGF-I signaling pathways involve mitogen-activated protein (MAP) kinase and phosphatidylinositol-3 kinase (PI-3 kinase). Treatment with 10(-7) M of the MAP kinase inhibitor PD098059 and 10(-5) M of the PI-3 kinase inhibitor LY294002 decreased IGF-I-induced BrdU-uptake in the endometrial stromal cells. However, LY294002 (10(-5) M) also decreased the BrdU-uptake in the absence of IGF-I treatment. These results suggest that endometrial IGF-I is involved in the proliferation of endometrial stromal cells in a paracrine or autocrine manner, and that the MAP kinase pathway is involved in DNA replication of endometrial stromal cells.     

An Immunohistochemical Observations on the Oviduct of the Goat

The oviduct has an important role in regulating transport of gametes and fertilization. The main role in these functions has a smooth muscle cells and ciliated epithelium lining the oviduct. All functions are under the influence of hormonal and nervous system. The objective of this study was immunohistochemically to examine the following structures: lining epithelium, smooth muscle cells, elastic fibres and nerve fibres. For this purpose, the following antibodies were used: cytokeratin 18, S‐100 protein, acetylated α‐tubulin, smooth muscle actin, desmin and elastin. Ciliary and secretory cells of the lining epithelium were positive for cytokeratin 18 and S‐100 protein. Cilia and the basal body‐associated structures of ciliary cells were positive to acetylated α‐tubulin. Smooth muscle cells (SMC) in mucosa and of the muscular layer were positive for α‐smooth muscle actin (SMA) and desmin. High density of nerve fibres positively reacted to acetylated α‐tubulin and S100 protein was present in the mucosa, muscular layer and serosa. Elastic fibres positive for elastin form a dense network at the base of the mucosal folds and in the muscle layer. A dense network of these fibres is accompanying the blood vessels. It is supposed that together with smooth muscle cells they are involved in the transport of ovum and in blood flow regulation.     

八点黑獭兔不同发育时期子宫组织结构变化的研究

观察母兔妊娠20、26、29天和15、30、60、90日龄八点黑獭兔的子宫组织,以探讨八点黑獭兔子宫的形态学发育特点。结果表明：獭兔的子宫随着年龄的增长．其内膜的粘膜上皮由假复层柱状纤毛上皮逐渐分化成紧密规则的单层柱状上皮;固有层在15～30日龄之间出现．内含大量间质细胞;妊娠期固有层发生水肿和充血;子宫肌层在幼龄时分层不明显,各层肌纤维互相交织,随平滑肌细胞分裂增生,3月龄时肌层出现明显的内环、外纵两层,中间形成一层环状排列的血管：獭兔出生后其子宫内膜腺由子宫内膜上皮细胞内陷形成,随后腺上皮细胞经有丝分裂增生,15日龄幼兔已形成单管子宫腺。该研究结果可为兔的解剖学、生殖生理学增添新的内容,也为进一步研究兔生殖系统疾病的治疗与预防提供参考资料。     

Is Mechanically Induced Cystic Endometrial Hyperplasia (CEH) a Suitable Model for Study of Spontaneously Occurring CEH in the Uterus of the Bitch?

Cystic endometrial hyperplasia (CEH) was experimentally reproduced by the intraluminal insertion of a silk wire in the uterus of metestral bitches to obtain a model for the study of spontaneously occurring CEH in the bitch. This mechanically reproduced CEH corresponded histologically very well to spontaneously occurring CEH. With respect to sex hormone receptor expressions, however, there was no similarity. In the mechanically induced CEH, progesterone receptor expression was reduced in the epithelial cells (surface epithelium and endometrial glands) and slightly increased in the stromal fibroblasts and myometrium as compared with the normal metestrus uterus. The oestrogen receptor expression in mechanically induced CEH was reduced in the epithelial cells (surface epithelium and endometrial glands) and more or less unchanged in the stromal fibroblast and myometrium as compared with the normal metestrus uterus. This is in contrast to the increased sex hormone receptor expressions in all uterine cell types, observed in spontaneously occurring CEH. The mechanically induced CEH model corresponds immunohistochemically more to early placentation and to pyometra in the bitch. Thus this experimental CEH model is not suitable for pathogenic studies of spontaneously occurring CEH in the bitch.     

The distribution and immunolocalization of fibroblast growth factors (FGFs) in the rat oviduct during early pregnancy and the post-partum period

The mammalian oviduct provides a favourable environment for several reproductive processes, including ovum transport, sperm capacitation, fertilization and pre-implantation embryonic development. This environment is regulated by cyclic ovarian steroids, that is oestrogen, and growth factors. Fibroblast growth factors (FGFs) regulate the differentiation and growth of various cell types in the female genital tract. This study aimed to determine the localization of FGF1, FGF2, FGF receptor 1 (FGFR1) and 2 (FGFR2) in the rat oviduct, by immunohistochemistry, on day 5 of pregnancy and post-partum days 1, 3 and 5, and to demonstrate the possible functions of these proteins during early pregnancy and the post-partum period. On all examination days, cytoplasmic and nuclear FGF1 immunoreactivity was detected in the epithelium lining the infundibulum, ampulla and isthmus of the oviduct. Immunoreactivity was much stronger in the basal bodies of the cilia on the epithelium lining the infundibulum and ampulla. FGF1 immunoreactivity was also detected in stromal cells, myocytes and endothelial cells. Cytoplasmic FGF2 immunoreactivity was observed in the tunica muscularis, vascular myocytes and endothelial cells. While strong cytoplasmic FGF2 immunoreactions were observed in the stromal cells of the lamina propria, the luminal epithelium, some stromal cells and smooth muscle cells displayed a rather weak FGFR1 and FGFR2 immunoreactivity. Immunoreaction intensity did not differ between the periods examined. This study shows that FGF1, FGF2, FGFR1 and FGFR2 are produced by rat oviduct cells during pregnancy and the post-partum period, and reproductive physiology is regulated not only by hormonal mechanisms, but also by growth factors.