瘦素、胰岛素及IL-6对平滑肌细胞瘦素受体mRNA表达的影响

目的研究瘦素、胰岛素及IL-6对平滑肌细胞瘦素受体(Ob-R)mRNA表达的影响。方法采用六孔板培养皿培养鼠平滑肌细胞,5个孔作为一个浓度组,通过半定量的RT-PCR方法,分别观察了不同浓度的大鼠瘦素、胰岛素及IL-6对平滑肌细胞瘦素受体mRNA表达水平的影响。结果通过半定量RT-PCR,我们检测了短型瘦素受体(Ob-Ra)和长型瘦素受体(Ob-Rb)的mRNA表达水平,瘦素受体(Ob-R)mRNA表达水平随着瘦素及IL-6浓度增加而上升,随着胰岛素的浓度增加而下降。结论瘦素及IL-6可在体外上调平滑肌细胞瘦素受体的表达,胰岛素可下调平滑肌细胞瘦素受体的表达。这三个因子参与了瘦素受体的表达调控,对我们了解瘦素抵抗的发生机制有重要意义。     

高原鼠兔褪黑素受体在下丘脑-垂体-性腺轴中的表达分析

褪黑素在季节性繁殖动物的生殖细胞发育与性腺功能调控中发挥重要作用,然而褪黑素如何通过下丘脑-垂体-性腺（HPG）轴实现其调控功能目前仍不清楚。因此,本研究选取典型的长日照动物——高原鼠兔（Ochotona curzoniae）作为研究对象,使用酶联免疫吸附法测定繁殖期与非繁殖期雌雄鼠兔的血清褪黑素水平昼夜变化,利用实时荧光定量PCR分析褪黑素受体基因Mtnr1a与Mtnr1b在下丘脑、垂体与性腺中的表达水平,并通过免疫荧光染色进一步确认两种受体在性腺不同类型细胞中的定位。结果显示,非繁殖期雄性鼠兔的血清褪黑素含量始终高于繁殖期,且呈现不同的昼夜变化模式;雌性鼠兔的血清褪黑素含量远低于雄性鼠兔,且在繁殖期与非繁殖期并不存在显著差异。Mtnr1a与Mtnr1b在下丘脑、垂体与性腺中均有表达,雄性鼠兔在下丘脑与垂体中表现出繁殖期与非繁殖期基因表达的显著差异,而雌性鼠兔基因表达的差异主要出现在垂体与性腺中。两种受体蛋白在雄性性腺生殖细胞和支持细胞中均有分布,但MTNR1A更局限于精原细胞内,MTNR1B则在管腔内生殖细胞中表达。雌性性腺中MTNR1A在卵母细胞胞质内有表达,但更集中表达于颗粒细胞;MTNR1B在颗粒细胞以及卵母细胞核质内均有表达,且在生长卵泡的卵泡膜细胞中呈现高表达。以上结果表明,褪黑素调控雌雄高原鼠兔季节性繁殖的模式并不相同,其作用不仅限于通过下丘脑-垂体-性腺轴的间接调控,也可能通过性腺内靶向受体直接影响生殖细胞与体细胞命运。     

胍基丁胺在成年大鼠组织中的表达和分布

目的观察胍基丁胺（agmatine,AGM）在成年Wistar大鼠全身组织的表达和分布。方法采用免疫组织化学法,用自制的抗胍基丁胺多克隆抗体检测胍基丁胺在成年Wistar大鼠全身组织中的表达分布情况。结果胍基丁胺在胃、十二指肠、空肠、回肠、结肠的粘膜腺上皮细胞胞质内呈强阳性表达;胍基丁胺在大脑皮层、丘脑、海马、延髓的神经元胞质和神经轴突内呈强阳性表达;胍基丁胺在子宫、输卵管、前列腺的腺上皮细胞和睾丸的生精细胞胞质内呈强阳性表达;胍基丁胺在肝细胞、肾上腺皮髓质细胞胞质内呈阳性表达,在肾脏、脾脏呈弱阳性表达;胍基丁胺在肺、阴茎的微血管平滑肌细胞胞质内呈强阳性表达,但在心脏、骨骼肌、食道、主动脉的肌细胞内未见其表达。结论胍基丁胺在成年Wistar大鼠体内广泛分布,可能具有重要的生理作用。     

Ghrelin、KGF、TGF-β(β2、β3)在大鵟胃肠道中的表达

应用免疫组织化学方法和体视学半定量方法,检测了ghrelin、KGF、TGF-β(TGF-β_2,TGF-β_3)在大鵟(Buteo hemilasius)胃肠道中的表达,利用IPP专业图像分析软件对其表达强度进行了定量分析.结果表明,ghrelin免疫反应阳性物质分布在十二指肠、空肠、回肠、盲肠和直肠的黏膜层,主要分布于黏膜上皮、肠腺上皮和固有层.从十二指肠到盲肠阳性细胞的分布密度逐渐减小,直肠阳性细胞的分布密度高于盲肠.胃肠道呈KGF免疫反应阳性,胃内阳性物质分布于腺胃浅腺和深腺、肌胃黏膜、肌胃单管腺的上皮细胞;肠内阳性物质分布于固有层的血管、淋巴和平滑肌纤维.胃黏膜、腺胃深腺、肌胃单管腺、肠道黏膜、肠腺呈TGF-β_2及TGF-β_3免疫反应阳性,阳性物质分布于黏膜、肠腺上皮细胞胞质中.图像分析显示,KGF的阳性表达水平呈波浪形变化,在空肠和直肠处达到峰值;TGF-β2的阳性表达水平呈波浪形变化,分别在肌胃和空肠处有峰值;TGF-β_3从腺胃到空肠阳性表达水平逐渐增强,之后阳性表达水平又逐渐下降,到盲肠阳性表达水平回升.ghrelin、KGF、TGF-β_2和TGF-β_3的阳性表达强弱可能与胃肠道的消化能力有关,它们的协同表达调控鸟类胃肠道的生长和发育.     

大熊猫胃肠道神经肽Y和长型瘦素受体的表达

为了观察神经肽Y(NPY)和瘦素长型受体(OB-Rb)在大熊猫胃肠道的表达分布,并探讨其功能。本实验选用中国保护大熊猫研究中心濒危动物繁殖与保护遗传四川省重点实验室提供的3例大熊猫胃肠组织样品,采用HE和免疫组化SABC法进行组织学、NPY及OB-Rb蛋白的表达研究。HE染色结果显示3例大熊猫胃肠道组织学结构完整,主要表现在单细胞和多细胞黏液腺丰富、小肠绒毛较长,肠道黏膜肌层与肌肉层较厚等。免疫组化方法观察到NPY和OB-Rb阳性产物广泛分布于大熊猫的胃肠道中。NPY阳性神经纤维呈串珠状或点状排列,主要位于黏膜下神经丛和肌间神经丛内,前者阳性神经纤维数量较多。NPY阳性细胞主要分布于黏膜层和肠腺,多呈椭圆形、多边形等。OB-Rb阳性产物主要分布在黏膜层,且在固有层内有大量阳性细胞分布。表明NPY和OB-Rb在大熊猫肠道中的广泛表达,为研究NPY和OB-Rb影响肠道的生长发育、消化吸收、免疫等多种功能奠定了基础。     

雄激素受体在肝癌发生过程中的表达及意义

为了进一步探讨雄激素受体（ＡｎｄｒｏｇｅｎＲｅｃｅｐｔｏｒ,ＡＲ）作为肝癌标志物的意义,本文采用免疫组织化学ＡＢＣ法,对二乙基亚硝胺（ＤＥＮ）诱发大鼠肝癌发生过程中肝细胞雄激素受体（ＡＲ）的表达进行了系统观察。结果显示：正常大鼠的ＡＲ阳性肝细胞极少,ＤＥＮ诱癌第４周可见少量肝细胞呈ＡＲ阳性表达,细胞散在分布,胞质和／或胞核内可见棕褐色阳性反应颗粒。随着肝癌发展进程,ＡＲ阳性肝细胞数逐渐增多,呈簇状或片状分布。至诱癌第１８周,肝癌结节内肝癌细胞大多呈ＡＲ阳性表达。本实验结果表明,ＡＲ与肝癌的发生和发展具有密切关系     

雌激素受体在老年和青年猕猴下丘脑中表达的比较

为了观察老年猕猴下丘脑中雌激素受体的表达及变化情况,运用免疫组织化学SABC 法,对青年和老年猕
猴下丘脑雌激素受体的表达特点进行了研究。结果发现,雌激素受体免疫阳性细胞主要分布于下丘脑的室周灰
质、室旁核、腹外侧核、腹内侧核、弓状核等,雌激素受体阳性产物主要定位于细胞核和细胞质中。与青年猕
猴比较,老年猕猴下丘脑各个核团的雌激素受体在表达强度及阳性细胞数量上均显著或极显著低于青年猕猴
(P<0.05 或 P<0.01)。表明,老年猕猴下丘脑雌激素受体的表达显著低于青年猕猴,可能为老年猕猴雌激素缺
乏所致。     

非基因型雌激素膜性受体GPR30在生后雌性大鼠海马内的发育学表达与亚细胞水平定位研究

为了研究非基因型雌激素膜性受体GPR30对海马的结构和功能的调节作用,应用硫酸镍铵增强显色的免疫组化技术以及酶标免疫电镜技术,观察了生后雌性大鼠海马内GPR30表达的变化及其免疫阳性产物在神经元亚细胞水平的定位情况．结果显示,GPR30免疫阳性产物主要位于海马CA区的锥体层神经元与齿状回颗粒层的神经元内,其表达水平随发育呈增加趋势．P0时在雌性大鼠海马未发现明显GPR30免疫阳性反应,P7后免疫阳性物质开始在CA2出现,P14时见于 CA1、CA2和齿状回,P30和P60主要见于CA1、CA2、CA3和齿状回．在光镜下,GPR30免疫阳性产物位于细胞核外的胞浆中,细胞核未见免疫阳性反应．在透射电镜下可见其位于神经元的胞浆内,可能主要是粗面内质网,也可见于线粒体和细胞膜．以上结果证实,GPR30是一种位于细胞核外的、非基因型作用的雌激素受体,可能参与了雌激素对海马锥体神经元突触可塑性和学习记忆等功能的调节,还可能参与了对齿状回成年神经干细胞某些活动的调节．     

黄颡鱼仔稚鱼胃肠发育的显微和超微结构研究

利用光学显微技术和透射电镜技术,观察和研究了出膜后1-35日龄黄颡鱼(Pelteobagrus fulvidraco)仔稚鱼的胃肠发育.水温为23-25℃时,2日龄仔稚鱼的消化道分化出口咽腔、食道、胃、肠;3日龄肠道分化为前肠、中肠、后肠.3日龄黄颡鱼开口摄食时其胃贲门部黏膜层下出现胃腺,为已有鱼类研究报道中胃腺最早出现的日龄.超微结构显示3日龄胃腺细胞中可见胃蛋白酶原颗粒和丰富的管泡系统,为典型的泌酸胃酶细胞;随日龄增加,胃蛋白酶原颗粒越来越丰富而管泡系统越来越不明显.3日龄时前肠吸收细胞胞质中可见脂肪泡,后肠吸收细胞胞质中可见蛋白质胞饮体.直到25日龄后肠吸收细胞胞质中尚可见蛋白质胞饮体.以七结果表明黄颡鱼在3日龄开口摄食时消化道具备细胞外消化功能,但此功能不完善,期间继续通过胞饮作用等细胞内消化来弥补胞外消化的不足,直到25-30日龄后细胞外消化功能发育完善.采用符合其生理机能发育过程的投喂管理策略可以有效提高大规格苗种培育的成活率.     

Bax蛋白在大鼠肝癌发生过程中的表达和意义

通过动态观察Bax蛋白在实验性大鼠肝癌发生过程中肝细胞的表达,探讨Bax蛋白与肝癌发生的关系及其生物学意义。用DEN饲喂大鼠,分别于第4、8、12、16、18周处死大鼠,取其肝脏,石蜡切片,ABC法免疫组织化染色。结果显示：正常成年大鼠肝细胞均有中等程度Bax蛋白表达。至诱癌第4周大鼠肝小叶内有少数肝细胞呈Bax蛋白免疫阳性反应,随诱癌发展进程,呈Bax蛋白免疫阳性反应肝细胞进一步减少,第12周,只可见肝细胞增生结节的多数肝细胞呈Bax蛋白免疫阳性反应。诱癌晚期（第18周）,癌结节内肝癌细胞均呈Bax免疫反应阳性,其强度较正常肝细胞明显增强,Bax蛋白免疫反应产物为胞质内粗大的棕褐色颗粒。部争肝细胞胞质和胞膜均呈阳性,肝癌细胞最为常见。结果表明：Bax蛋白表达减少或缺失是肝癌发生过程中的早期事件,可能参与肝癌的启动过程。     

Hormone-sensitive lipase expression and IHC localization in the rat ovary, oviduct, and uterus

Hormone-sensitive lipase (HSL) is a key regulator of cholesterol esters metabolism. The aim of this study was to determine HSL localization in rat female reproductive organs during the ovarian cycle by IHC methods. HSL was located in the ovarian epithelium. The granulosa cells and oocytes of primordial follicles were immunonegative. In mature follicles, HSL was found in oocytes and theca and granulosa cells. However, HSL expression in theca cells and oocytes decreased during follicular atresia. Luteal cells showed HSL staining in cytoplasm during proestrus and estrus, in the nucleus during metestrus, and in cytoplasm and the nucleus during diestrus. In the tubaric ampulla, HSL was located in the epithelial cells nuclei and in the cilia during proestrus and estrus but mainly in the nucleus during metestrus and diestrus. In the isthmus, cells showed HSL immunolabeling in the nucleus and cilia during proestrus, but only in the cilia during estrus, metestrus, and diestrus. In the uterus, HSL was found in the epithelial cells nuclei. HSL-immunoreactive bands at 84, 67, 54, and 43 kDa were found in rat female reproductive organs. HSL labeling in the nucleus of epithelial and germ cells suggests an as yet unknown function for this protein, probably related to oogenesis and cell proliferation.     

Variations in parametrial white adipose tissue mass during the mouse estrous cycle: relationship with the expression of peroxisome proliferator-activated receptor-gamma and retinoic acid receptor-alpha

Estrogen and progestin participate in the regulation of adipose tissue metabolism, and peroxisome proliferator-activated receptor-gamma (PPARgamma) and retinoic acid receptor-alpha (RXRalpha) are absolutely required for adipose tissue development. The present study is to investigate the changes in parametrial fat mass and expression of PPARgamma and RXRalpha during estrous cycle in mice. Parametrial white adipose tissues (WAT), inter-scapula brown adipose tissues, and uteri from female mice were weighed. Blood samples were collected for the measurement of 17 beta-estradiol and progesterone levels. An RNase protection assay and Western blot analysis were used to compare the expression of PPARgamma and RXRalpha in adipose tissue. The mass of parametrial WAT in diestrus was significantly higher compared with estrus. However, there is no significant difference on the mass of brown adipose tissues during estrous cycle. The expression of PPARgamma in WAT in diestrus was significantly higher than that in estrus. The expression of RXRalpha during estrous cycle was unchanged in both white and brown adipose tissues. In conclusion, the variation in parametrial WAT mass during the mouse estrous cycle correlates with changes in the expression of PPARgamma in WAT.     

Localization of metallothionein in female reproductive organs of rat and guinea pig

We demonstrated the localization of metallothionein (MT) in rat uterus and ovaries and in guinea pig mammary glands. During the cyclic changes from one estrous period to the next, strong MT immunostaining was found in the glandular epithelium of the endometrium and weak immunostaining was observed in the simple columnar epithelium. Interestingly, during estrus, the intensity of MT immunostaining decreased in the cytoplasm, whereas during metestrus, diestrus, and proestrus the intensity of strong and similar immunostaining was observed in both the cytoplasm and nucleus. During proestrus and estrus, the number of vaginal epithelial cells containing MT increased on the luminal side of the epithelium and inside the lumen. In rat ovary, strong immunostaining was observed in the cytoplasm and nucleus of granulosa-lutein cells of the corpus luteum and in the cytoplasm of the ovum. In mammary gland of non-pregnant guinea pig, very strong but scattered MT immunostaining was demonstrated in both cytoplasm and nucleus of some epithelial cells of the lactiferous ducts. The mammary tissue of the pregnant guinea pig showed an increase in MT staining in alveolar cells that had proliferated due to pregnancy. The presence of MT in the female reproductive organs, the tissues of which actively grow under the control of female sex hormones, indicates some as yet unknown association of MT with cell proliferation and differentiation.     

QRFP in female rats: effects on high fat food intake and hypothalamic gene expression across the estrous cycle

Pyroglutamylated arginine-phenylalanineamide peptide (QRFP) is a neuropeptide involved in feeding behavior. Central administration of QRFP selectively increases the intake of a high fat diet in male rats. QRFP administration also stimulates the hypothalamic-pituitary-gonadal axis via gonadotrophin-releasing hormone in male and female rats. Prepro-QRFP mRNA is expressed in localized regions of the mediobasal hypothalamus which are abundant in neurotransmitters, neuropeptides and receptor systems important for food intake regulation and reproductive behaviors. The current experiments were conducted to investigate the effects of centrally administered QRFP-26 on the intake of a high fat diet (HFD, 60% kcal from fat) in female rats and to investigate alterations in hypothalamic prepro-QRFP and its receptors, GPR130a and GPR103b, mRNA levels over the estrous cycle. In Experiment 1, female rats were administered QRFP-26 (intracerebroventricular; 0.3 nmol, 0.5 nmol, 1.0 nmol) in rats consuming either a HFD or a low fat diet. All doses of QRFP-26 selectively increased the intake of the HFD in female rats. These data suggest that QRFP-26 regulates the intake of energy dense foods in female rats, which is similar to previous findings in male rats. In Experiment 2, hypothalamic levels of prepro-QRFP mRNA and its receptors were assessed during diestrus, proestrus, or estrus. The level of prepro-QRFP mRNA in the ventromedial/arcuate nucleus (VMH/ARC) of the hypothalamus was increased during proestrus, which suggests that endogenous estrogen levels regulate QRFP expression in the VMH/ARC. These data suggest that QRFP may play a role in coordinating feeding behaviors with reproductive function when energy demand is increased.     

Messenger RNA levels of estrogen receptors alpha and beta and progesterone receptors in the cyclic and inseminated/early pregnant sow uterus

The aim of the present study was to investigate differences in the expression of mRNAs for ERalpha, ERbeta and PR in the sow uterus at different stages of the estrous cycle as well as in inseminated sows at estrus and during early pregnancy by use of solution hybridization and in relation to plasma levels of estradiol and progesterone. Uterine samples were collected at different stages of the estrous cycle and after insemination/early pregnancy. In the endometrium, the expression of ERalpha mRNA and PR mRNA was similar for cyclic and early pregnant groups. Both were highest at early diestrus/70 h after ovulation and ERalpha mRNA was lowest at late diestrus/d 19 while PR mRNA was lowest at diestrus and late diestrus/d 11 and d 19. The expression of endometrial ERbeta was constantly low during the estrous cycle but higher expression was found in inseminated/early pregnant sows at estrus and 70 h after ovulation. In the myometrium, high expression of ERalpha mRNA and PR mRNA was observed at proestrus and estrus in cyclic sows and at estrus in newly inseminated sows. Higher expression of myometrial ERbeta mRNA was found in inseminated/early pregnant sows compared with cyclic sows, although significant only at estrus. In conclusion, the expression of mRNAs for ERalpha, ERbeta and PR in the sow uterus differed between endometrium and myometrium as well as with stages of the estrous cycle and early pregnancy. In addition to plasma steroid levels, the differences between cyclic and inseminated/early pregnant sows suggest that other factors, e.g. insemination and/or the presence of embryos, influence the expression of these steroid receptor mRNAs in the sow uterus.     

Slight influence of the estrous cycle stage on the mucosal and systemic specific antibody response induced after vaginal and intraperitoneal immunization with protoxin Cry1Ac from Bacillus thuringiensis in mice

Since the immune response appears to be variable according to the hormonal stage of the mammalian female, the aim of this study was to determine whether estrous cycle stage modifies the mucosal and systemic immune responses induced by intraperitoneal and vaginal immunization of mice with protoxin Cry1Ac. We tested the influence of three immunizations on the specific antibody response elicited at estrus and diestrus, that were the same estrous cycle stages at which the antigen was applied. Both intraperitoneal and vaginal immunization of mice with Cry1Ac either at estrus or diestrus induces specific antibody responses at serum, vagina and large intestine. The stage of the estrous cycle have little or non influence in the magnitude of the response induced, since only at serum the IgM was slightly higher at estrus than at diestrus by both routes. At the large intestine only the IgA response elicited via the intraperitoneal route changed, being higher at diestrus, whereas at the vagina IgA response induced did not change significantly due to the cycle stage. Present results suggest that Cry1Ac may be used as an antigen carrier as it can elicit antibody responses at systemic level and at several mucosal sites including the vagina that are not modified significantly throughout the reproductive cycle.     

Immunolocalization of cubilin, megalin, apolipoprotein J, and apolipoprotein A-I in the uterus and oviduct

Spermatozoa maturation and capacitation occurring in the male and female reproductive tracts, respectively, involves the remodeling of the spermatozoa plasma membrane. Apolipoprotein J (apoJ) and apolipoprotein A-I (apoA-I) have been implicated in the process of lipid exchange from the spermatozoa plasma membrane to epithelial cells lining the male reproductive tract. Evidence suggests that this process is mediated by the cooperative action of the endocytic lipoprotein receptors megalin and cubilin, which are expressed at the apical surface of absorptive epithelia in various tissues, including the efferent ducts and epididymis. Here, we investigated the possibility that these receptors and their lipid-binding ligands, apoJ and apoA-I, might function similarly in the female reproductive tract. We show that megalin and cubilin are expressed in the uterine epithelium at all stages of the estrous cycle, maximally during estrous and metestrous stages. In the oviduct, there is pronounced expression of both megalin and cubilin in the nonciliated cells of the proximal oviduct and epithelial cells of the distal oviduct, particularly during estrous and metestrous stages. In both uterine and oviduct epithelial cells, megalin and cubilin were located on the apical regions of the cells, consistent with a distribution at the cell surface and in endosomes. ApoJ and apoA-I were both detected in apical regions of uterine and oviduct epithelial cells. Secretory cells of the uterine glands were found to express apoJ and apoA-I suggesting that the glands are a site of synthesis for both proteins. In summary, our findings indicate that megalin and cubilin function within the female reproductive tract, possibly mediating uterine and oviduct epithelial cell endocytosis of apoJ/apoA-I-lipid complexes and thus playing a role in lipid efflux from the sperm plasma membrane, a major initiator of capacitation.     

The effect of different stages of the sex cycle on rat behavior in a plus maze

Anxiety and motor activity of female white rats in the elevated plus-maze were studied at different stages of the reproduction cycle (estrus, diestrus, pregnancy and lactation). The level of anxiety was lower, and that of locomotor and exploratory activity was higher during estrus and lactation than during diestrus and pregnancy. Exposure to chronic pain of threshold intensity did not induce behavioral changes in pregnant rats. There was no difference between the control and experimental animals in the level of plasma corticosterone.     

Effects of stress upon the oxidative metabolism and its correlation with gastric ulcer formation: the role of sex.

The metabolic-oxidative activity of different nervous and glandular structures (amygdala, hypothalamus, lateral-frontal cerebral cortex, adrenal glands) in male and female rats under acute stress caused by physical immobilization, was determined. The sexual cycle of the female rat was controlled by examination of their vaginal frotis. One experimental group during estrus and another one during diestrus were selected. At the same time ovariectomy was performed on an experimental group in order to eliminate the hormonal influences of the ovary. Results show there are no significant differerneces in the oxidative metabolism. Nor in the numbers of ulcers. Hypothalamus-hypophyseal-adrenocortical activation was made manifest on obtaining significant differences in the weight of the adrenal glands, a fact long ago reported in a number of studies. Necropsy showed severe gastric hemorrhages and ulcer in the stomach. Nevertheless, no significant differences between the distinc experimental groups were obtained. The likely participation of sexual hormones in female rats is discussed in the light of our results.     

Distribution and Regulation of ENaC Subunit and CFTR mRNA Expression in Murine Female Reproductive Tract

The present study investigated the regional distribution and cyclic changes in the mRNA expression of epithelial Na+ channel (ENaC) subunit and cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated Cl- channel, in adult female mouse reproductive tract. In situ hybridization revealed that in contrast to the abundant expression of CFTR, ENaC (alpha, beta, gamma) mRNA signal was not detected throughout the estrus cycle in the ovary and oviduct. Messenger RNA for all ENaC subunits was abundantly detected in the cervical and vaginal epithelia throughout the estrus cycle but for CFTR, mRNA was found only at proestrus. In the uterine epithelium, alphaENaC mRNA was detected at diestrus but not found at any other stage, while CFTR mRNA was only detected at early estrus but not other stages. Semi-quantitative RT-PCR detected mRNA for all ENaC subunits in the uterus throughout the cycle with maximal expression at diestrus and CFTR mRNA was only found in the early stages of the cycle. The involvement of ENaC and CFTR in Na+ absorption and Cl- secretion was demonstrated in cultured endometrial epithelia using the short-circuit current technique and found to be influenced by ovarian hormones. Taken together, these data indicate a main secretory role of the ovary and oviduct and a predominantly absorptive role of the cervix and vagina. The present results also suggest an ability of the uterus to secrete and absorb at different stages of the estrus cycle. Variations in the fluid profiles may be dictated by the regional and cyclic variations in expression of ENaC and CFTR and are likely to contribute to various reproductive events in different regions of the female reproductive tract.