RESUMO
This study evaluated whether the treatment of pseudopregnancy in bitches with vitamin B6 modulates uterine expression of receptors for progesterone (PR), oestrogen (ERα), androgen (AR), thyroid hormone (TRα) and the kisspeptin/Kiss1r system. Eighteen pseudopregnant bitches were treated for 20 days in groups receiving placebo (n = 6); cabergoline (5 µg/kg/day; n = 6); or vitamin B6 (50 mg/kg/day; n = 6). Blood was collected on the 1st day of drug administration and 120 h later to measure serum prolactin (PRL). After treatment, they were ovariohysterectomized and uterine fragments were collected for histomorphometry and immunohistochemical evaluation of PR, ERα, AR, TRα, Kiss1 and Kiss1r. After 120 h of cabergoline or vitamin B6 treatment, PRL levels were reduced in the bitches, confirming the antiprolactinemic effect of these drugs. Furthermore, regardless of treatment, the animals exhibited uterine histomorphometry consistent with dioestrus. The PR showed strong immunostaining in all regions and an increase in scores was observed for this receptor in animals treated with vitamin B6 in deep glands. In contrast, ERα and Kiss1R receptors showed weak to no immunostaining in all uterine regions and no changes between groups. Regarding AR, most animals treated with vitamin B6 showed increased trends in the deep gland and myometrium marking scores. In contrast, in both vitamin B6 and cabergoline treatments, a reduction in TRα marking scores was observed compared to the control group. In addition, on the endometrial surface, a reduction was observed in the marked area of Kiss1 after administration of cabergoline when compared to the pseudopregnant control group. These findings shed valuable insight into the use of vitamin B6 as a drug with actions similar to cabergoline in reducing PRL and uterine modulation in bitches.
Assuntos
Cabergolina , Kisspeptinas , Prolactina , Pseudogravidez , Útero , Animais , Feminino , Cães , Kisspeptinas/farmacologia , Kisspeptinas/metabolismo , Útero/efeitos dos fármacos , Útero/metabolismo , Cabergolina/farmacologia , Prolactina/metabolismo , Pseudogravidez/veterinária , Pseudogravidez/metabolismo , Receptores de Progesterona/metabolismo , Receptores Androgênicos/metabolismo , Ergolinas/farmacologiaRESUMO
Vaginocervical stimulation (VCS) induces twice-daily prolactin (PRL) surges resulting in pseudopregnancy in the rat. Furthermore, activation of the extracellular signal-regulated kinase-1/2 (Erk-1/2) is involved in the effect of estradiol (E2) on the Prl gene expression in pituitary cells. Herein, we investigated whether Erk-1/2 signaling is involved in the control of Prl expression in the pituitary of VCS rats and whether VCS regulates the effect of E2 on Erk-1/2 and Prl in the pituitary. Estrous rats were assigned as control or VCS groups and 0, 6, 12 or 24h later the levels and localization of phosphorylated Erk-1/2 (p-Erk-1/2) were analyzed in the pituitary. The effect of an Erk-1/2 inhibitor PD98059 on the Prl level in the pituitary of control or VCS rats was also analyzed. Other control or VCS rats were treated with E2 and the level of p-Erk-1/2 and Prl were measured in the pituitary. In control rats, p-Erk-1/2 decreased at 6 and 12h and increased at 24h while Erk-1/2 was phosphorylated at all time points in VCS rats. p-Erk-1/2 was localized only in the anterior pituitary. PD98059 decreased Prl level in VCS, but not in control rats. Estradiol decreased Erk-1/2 phosphorylation although did not change Prl level in the pituitary of control or VCS rats. These findings show that prolonged activation of Erk-1/2 is necessary to induce Prl expression in the pituitary of VCS rats; however, VCS does not influence the role of E2 on the activation of Erk-1/2 and Prl expression the pituitary.
Assuntos
Expressão Gênica , Sistema de Sinalização das MAP Quinases/fisiologia , Hipófise/metabolismo , Prolactina/genética , Pseudogravidez/genética , Animais , Feminino , Fosforilação , Prolactina/metabolismo , Pseudogravidez/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
The corpus luteum is a temporary endocrine structure in mammals that plays an important role in the female reproductive cycle and is formed from a ruptured and ovulated follicle with rapid angiogenesis. Vascular endothelial growth factor (VEGF) is thought to be vital in normal and abnormal angiogenesis in the ovary, but the molecular regulation of luteal VEGF expression during corpus luteum development in vivo is still poorly understood at present. Therefore, we examined whether hypoxia-inducible factor-1a (HIF-1a) is induced and regulates VEGF expression and luteal function in vivo using a pseudopregnant rat model treated with a small-molecule inhibitor of HIF-1a, echinomycin. Corpus luteum development in the pseudopregnant rat ovary was determined after measuring plasma progesterone concentration and ovarian prostaglandin F2a content to reflect changes in HIF-1a and VEGF on different days of this developmental process. At day 7, the corpus luteum was formed and the expression of HIF- 1a/VEGF reached a maximum, while a significant decrease in HIF-1a/ VEGF expression was observed when luteolysis occurred at day 13. Additionally, echinomycin blocked luteal development by inhibiting VEGF expression mediated by HIF-1a and following luteal function by detecting the progesterone changes at day 7. These results demonstrated that HIF-1a-mediated VEGF expression might be an important mechanism regulating ovarian luteal development in mammals in vivo, which may provide new strategies for fertility control and for treating some types of ovarian dysfunction, such as polycystic ovarian syndrome, ovarian hyperstimulation syndrome, and ovarian neoplasia.
Assuntos
Corpo Lúteo/crescimento & desenvolvimento , Dinoprosta/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Ovário/metabolismo , Progesterona/sangue , Pseudogravidez/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Corpo Lúteo/metabolismo , Manutenção do Corpo Lúteo , Feminino , Regulação da Expressão Gênica , Masculino , Gravidez , Pseudogravidez/sangue , Ratos , Ratos Sprague-Dawley , Transdução de SinaisRESUMO
Progesterone receptor (PR) plays an important role in mammals pregnancy which is characterized by greater progesterone plasma concentrations. We assessed PR protein distribution in the rabbit uterus by immunohistochemistry in two progestational conditions: pseudopregnancy (intact adult animals treated with hCG) and after application of a synthetic progestin, medroxyprogesterone acetate (MPA), to ovariectomized animals (OVX). PR immunoreactivity in uterine epithelium of pseudopregnant rabbits was increased in relation to non-pseudopregnant (NP) rabbits. Amounts were similar on Days 1, 3, and 5 of treatment, and was greater on Day 7 (P<0.001). In contrast, a significant diminution in PR immunoreactivity was observed in stroma cells from Days 1 to 7 (P<0.001). In OVX rabbits treated with MPA, an increase in PR immunoreactivity was observed in the uterine epithelium on Days 1 to 5 of treatment, reaching a maximum on Day 3 (P<0.001). In contrast, in stromal cells a diminution in PR immunoreactivity was observed when compared to the OVX group on Days 1, 3 and 7 of MPA treatment (P<0.001), and there was a slight increase on Day 5. Results suggest a differential time course and tissue specific immunoreactivity for PR in the uterus of the rabbit in two progestational conditions. The present study indicated synthetic progestins have different mechanisms of receptor regulation than those of natural hormones and it should be taken into account in reproductive applications.
Assuntos
Acetato de Medroxiprogesterona/farmacologia , Pseudogravidez/metabolismo , Receptores de Progesterona/metabolismo , Útero/efeitos dos fármacos , Útero/metabolismo , Animais , Gonadotropina Coriônica/farmacologia , Anticoncepcionais/farmacologia , Avaliação Pré-Clínica de Medicamentos , Feminino , Imuno-Histoquímica , Ovariectomia , Progesterona/sangue , Pseudogravidez/sangue , Pseudogravidez/patologia , Coelhos , Fatores de Tempo , Útero/patologiaRESUMO
Anandamide is an endocannabinoid known to participate in reproductive processes. This study observed that 17beta-oestradiol and progesterone modulated the production of anandamide and its metabolizing enzymes in the rat uterus. Anandamide production was highest at the oestrous stage and 17beta-oestradiol and progesterone stimulated its synthesis in ovariectomized rats. During early pregnancy, anandamide production remained constant on days 1-5 of gestation and diminished towards day 6. On day 6, implantation sites showed lower synthesis compared with interimplantation sites. In the delayed implantation model, 17beta-oestradiol inhibited anandamide synthesis compared with progesterone. During pseudopregnancy, anandamide production did not decrease towards day 6 as occurred during normal gestation. The administration of 17beta-oestradiol augmented anandamide production in rats on day 5 of pseudopregnancy; the treatment with mifepristone did not produce any change in anandamide synthesis. Anandamide-metabolizing enzymes were regulated by progesterone and 17beta-oestradiol. The effect of ovarian hormones on the synthesis of anandamide depends on different physiological conditions, oestrous cycle and early pregnancy, and on the presence of the activated blastocyst. Thus, ovarian hormones, as signals that emanate from the mother, operate in conjunction with the blastocyst intrinsic programme, regulating the synthesis of anandamide in a specific manner during crucial reproductive events that may compromise pregnancy outcome.
Assuntos
Ácidos Araquidônicos/biossíntese , Estradiol/farmacologia , Progesterona/farmacologia , Útero/efeitos dos fármacos , Amidoidrolases/genética , Amidoidrolases/metabolismo , Animais , Moduladores de Receptores de Canabinoides/biossíntese , Implantação do Embrião/efeitos dos fármacos , Implantação do Embrião/genética , Endocanabinoides , Ciclo Estral/efeitos dos fármacos , Ciclo Estral/genética , Ciclo Estral/metabolismo , Feminino , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Ovariectomia , Fosfolipase D/genética , Fosfolipase D/metabolismo , Alcamidas Poli-Insaturadas , Gravidez , Pseudogravidez/genética , Pseudogravidez/metabolismo , Ratos , Ratos Wistar , Fatores de Tempo , Útero/metabolismoRESUMO
Tissue kallikreins are present in rat uterus during the estrous cycle in luminal and glandular epithelium, in early gestation in the implantation node, and in the last third of pregnancy surrounding the sinusoids in the decidua basalis. The pattern of kinin B2 receptor expression, through which the vasoactive effect of kallikreins is exerted, was studied by in vitro autoradiography and immunohistochemistry. The kinin B2 receptor was observed in the luminal and glandular epithelium, myometrium, endothelial cells of arteries, veins and venules, and smooth muscle cells of endometrial and myometrial arterioles. Immunoblotting of crude membranes revealed a band of 69 kDa that increased in late proestrus and estrus, concordantly with the pattern of immunostaining observed in the tissue. At Day 7 of gestation, the kinin B2 receptor was expressed (binding sites and receptor protein) in the epithelium of the implantation node and decidual cells; these latter cells showed a further increase during gestational Days 9 and 10. From Days 14 to 21, the subplacental decidua became strongly immunoreactive, and on Days 16 and 21 the placental labyrinthine endothelium was intensely stained. During this period, endothelium of arteries and veins, smooth muscular cells of small diameter arterioles, and myometrium also expressed B2 receptors. In unilaterally oil-stimulated pseudopregnancy, the decidual cells and the glandular epithelium show similar immunoreactivity to that during pregnancy. The temporospatial pattern of kinin B2 receptors, coinciding with that of kallikrein or with sites accessible to the generated kinins, further supports an autocrine-paracrine role for the kallikrein-kinin system in the vasoactive changes of implantation and placental blood flow regulation.
Assuntos
Estro/metabolismo , Prenhez/metabolismo , Receptores da Bradicinina/metabolismo , Útero/metabolismo , Animais , Autorradiografia , Bradicinina/metabolismo , Membrana Celular/química , Membrana Celular/metabolismo , Endotélio Vascular/química , Epitélio/química , Feminino , Idade Gestacional , Imuno-Histoquímica , Músculo Liso Vascular , Miométrio/química , Gravidez , Pseudogravidez/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor B2 da Bradicinina , Receptores da Bradicinina/análise , Distribuição Tecidual , Útero/químicaRESUMO
The effect of exercise on mitochondria respiration was studied in gastrocnemius muscle of ovariectomized rats, pseudopregnant rats, and estrous rats. The estrous cycles were followed by vaginal smears. Rats were made pseudopregnant (PSP) by 45 s cervical stimulation with a glass rod on the day of estrous. The treadmill protocol (21 m/min, 10 grade uphill) induced a significant decrease in state 3 oxygen consumption (oxidative phosphorylation) in estrous (0.26 +/- 0.02 vs. 0.49 +/- 0.05 microatoms O min(-1) mg protein(-1)) and ovariectomized rats (0.18 +/- 0.03 vs. 0.40 +/- 0.03 microatoms O min(-1) mg protein(-1)). In contrast, pseudopregnant and progesterone-treated ovariectomized rats did not decrease state 3 nor state 4 respiratory rates. These results show that the effect of exercise on mitochondria respiration does vary according to the hormonal status.
Assuntos
Respiração Celular/fisiologia , Estrogênios/fisiologia , Mitocôndrias Musculares/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Respiração Celular/efeitos dos fármacos , Estro/fisiologia , Feminino , Glicogênio/metabolismo , Terapia de Reposição Hormonal , Ácido Láctico/metabolismo , Malato Desidrogenase/metabolismo , Mitocôndrias Musculares/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Ovariectomia , Progesterona/administração & dosagem , Pseudogravidez/metabolismo , Ratos , Ratos Sprague-Dawley , Succinato Desidrogenase/metabolismo , Água/metabolismoRESUMO
We explored the role of endogenous nitric oxide (NO) in the spontaneous motility of uterine tissue from pseudopregnant (psp) rats and the correlation between this action and the uterotonic prostaglandin (PG) E production. We worked in the early psp (on day 5 of psp), and in late psp (on day 8 and day 9). Treatment with N(G)-monomethyl-L-arginine L-NMMA (300 microM), a competitive nitric oxide synthase (NOS) inhibitor, did not modify isometric developed tension (IDT) and frequency of contractions (FC) on day 5 of psp; on day 8, tissue pretreated with L-NMMA showed an increase in the IDT and FC compared with controls, while on day 9 of psp, both IDT and FC showed a lower stability after treatment with the inhibitor. These data suggest that NO modulates uterine motility on day 8 (decreasing it) and on day 9 of psp (enhancing it). We also evaluated the total NOS activity and that of its isoforms at the three times mentioned, demonstrating that total NOS activity was higher on day 5 of psp and decreased with psp development. On day 5 of psp, calcium-dependent and calcium-independent NOS each forms around 50% of total NOS activity. On day 8 of psp, the calcium-dependent was the predominant NOS form, while on day 9 of psp, the uterine tissue showed a higher calcium-independent form of the enzyme. In view of the fact that we found an inhibitor effect of the endogenous NO in uterine contractility on day 8 of psp and an inverse action on day 9 of psp (enhancing uterine contractility), we suggest that the NOS calcium-dependent form could be responsible for uterine contractility in psp rats. Finally, we evaluated the relationship between endogenous NO and PGE production. We observed that on days 5 and 8 of psp, the L-NMMA (300 microM) treatment did not affect PGE production, but on day 9 of psp, the preincubation with the NOS inhibitor diminished PGE synthesis, suggesting that at this time endogenous NO can upregulate uterine PGE production. These results confirm that NO can modulate uterine motility by means of PGE production. In summary, we suggest that in uterine tissue from psp rats, the NO system can alternatively decrease or increase uterine contractions, this last effect by enhancing uterine PGE synthesis.
Assuntos
Óxido Nítrico/metabolismo , Prostaglandinas E/biossíntese , Contração Uterina/fisiologia , Útero/fisiologia , Animais , Inibidores Enzimáticos/farmacologia , Feminino , Masculino , Óxido Nítrico Sintase/efeitos dos fármacos , Óxido Nítrico Sintase/metabolismo , Gravidez , Pseudogravidez/metabolismo , Ratos , Ratos Wistar , Contração Uterina/efeitos dos fármacos , Útero/efeitos dos fármacos , ômega-N-Metilarginina/farmacologiaRESUMO
The present studies were carried out to characterize the cAMP-phosphodiesterase enzyme (PDE) in luteal cells recovered from pseudopregnant rats with streptozotocin-induced diabetes. A significant increase in the specific activity of the enzyme was detected in luteal cells from diabetic rats (Group D) with respect to control rats (Group C). This increase could not be prevented by insulin therapy (Group I). Luteal cells from Groups C and D rats responded in vitro to insulin by increasing their PDE activity (% of stimulus of specific activity: C = 75%, D = 110%). However, in cells isolated from Group I, the hormone caused an inhibition of PDE activity (% of inhibition of specific activity: 48%). When cytosolic fractions from Groups C, D and I were submitted to ion exchange chromatography, two PDE activity peaks could be observed and the activity of the different fractions was increased in the presence of Ca2+ and calmodulin. Nevertheless, the Ca(2+)-calmodulin effect was much lower in the extracts from Groups D and I than for controls. Kinetic studies of luteal PDE showed nonlinear Lineweaver-Burk graphs with two apparent ATP hydrolysis sites. Similar K(m) values were found for PDE from groups C, D, and I, whereas the Vmax2 for the enzyme was higher in Groups D and I. The endogenous concentration of cAMP, measured by RIA, showed no significant differences among Groups C, D, and I. On the basis of these results, we conclude that the specific activity of PDE is significantly increased in luteal cells from streptozotocin-induced diabetic animals, which could explain the previously described reduction in LH-stimulated progesterone production by luteal cells in diabetic rats.
Assuntos
3',5'-AMP Cíclico Fosfodiesterases/metabolismo , Diabetes Mellitus Experimental/metabolismo , 3',5'-AMP Cíclico Fosfodiesterases/isolamento & purificação , Animais , Calmodulina/farmacologia , Fracionamento Celular , Cromatografia por Troca Iônica , Feminino , Cinética , Ovário/enzimologia , Pseudogravidez/metabolismo , Ratos , Ratos Sprague-Dawley , SuperovulaçãoRESUMO
In previous studies, we found that the human estrogen-regulated heat shock protein (hsp) 27 (human homologue of rat hsp25) is modulated in the endometrium during the different phases of the menstrual cycle and that it is present in endometrial predecidual cells and in decidual cells attached to the placenta. In the present report, we describe the cell type-specific pattern of hsp25 expression in the rat uterus during the periimplantation period as well as during early and late decidualization and placentation. The hsp25 expression pattern was also analyzed in pseudopregnant rats with deciduomas. Immunocytochemistry was performed with an antibody generated against a chimeric hybrid protein containing the N-terminal of the murine hsp25 and the C-terminal of the human hsp27. During pregnancy at the time of implantation, hsp25 was expressed in the endothelial cells of the endometrial vessels and in the luminal epithelium of the antimesometrial region. As pregnancy advanced, hsp25 appeared in predecidual/decidual cells close to the implantation region and then expanded to the mesometrial region. This expression pattern was very similar during pseudopregnancy. Hsp25 was strongly expressed in trophoblastic giant cells beginning on Day 11 of gestation; less expression was noted in the junctional and labyrinth zones of the chorioallantoic placenta (in some cells lining the vascular spaces). In all the disparate cell types that expressed hsp25, the presence of the protein did not correlate with cell proliferation or with apoptosis but with the state of differentiation. Some placental PRL-family members with molecular weights similar to that of hsp25 are also present in antimesometrial decidua and in differentiated trophoblast giant cells; therefore, in this study we eliminated the possibility that our antibody was recognizing prolactin. We also determined that the hybrid hsp25/27 protein did not bind prolactin receptors, and noted that the hsp25 immunostaining pattern was not identical to that of decidual prolactin. In conclusion, the striking cell type-specific timing of hsp25 expression points to hsp25 as a molecule that is important during the implantation, decidualization, and placentation processes.
Assuntos
Proteínas de Choque Térmico , Proteínas de Neoplasias/biossíntese , Prenhez/metabolismo , Pseudogravidez/metabolismo , Útero/metabolismo , Animais , Membrana Celular/metabolismo , Células Epiteliais , Epitélio/metabolismo , Feminino , Proteínas de Choque Térmico HSP27 , Imuno-Histoquímica , Miométrio/citologia , Miométrio/metabolismo , Placenta/citologia , Placenta/metabolismo , Gravidez , Prolactina/metabolismo , Ratos , Ratos Wistar , Receptores da Prolactina/metabolismoRESUMO
There is substantial experimental evidence suggesting that oxytocin has a role in luteolysis in ruminates. Endogenous pulses of uterine prostaglandin (PG) F2 alpha occur synchronously with pulses of oxytocin during luteolysis; leading us to propose a possible feedback loop between uterine PGF2 alpha and luteal oxytocin. In rates, the mechanism whereby oxytocin acts has not been well elucidated. In the present report, the effects of an oxytocin receptor antagonist in pseudopregnant rats were investigated. Pseudopregnancy was induced in immature female rats by gonadotrophin treatment; this resulted in the formation of corpus luteum that remained functional for 9 +/- 1 days. The pseudopregnant rats were assigned to one of the following four groups. In the first group the relationship between the release of ovarian and uterine PGF2 alpha was tested. We also studied the serum progesterone during the pseudopregnancy. We found that PGF2 alpha released into the incubation medium from ovaries of pseudopregnant rats increased (p < 0.05) and was maximal on day 9 of pseudopregnancy. This concentration remained high until day 10 of pseudopregnancy and then decreased. The PGF2 alpha released from the uterus to the incubation medium rose (p < 0.05) on day 8 of pseudopregnancy and reached the peak value on day 10. the serum progesterone was increased (p < 0.001) on day 2 pseudopregnancy and was greater on day 5 (p < 0.001). The second and third group received a specific oxytocin receptor antagonist (1-deamino-2-O-methyltyrosine) in two different concentrations (0.05 or 0.2 mumol/l before the peak of PG release. Both doses employed decreased (p < 0.001) the release into the incubating medium of PGF2 alpha from ovaries and uterus. Indeed, after the treatment, the progesterone levels were higher (p < 0.001) than control on day 10 of pseudopregnancy. In the fourth group, a potent inhibitor of cyclooxygenase activity was administered on day 8 of pseudopregnancy into the ovarian bursa. The serum progesterone levels increased (p < 0.01) compared to control suggesting a possible role of ovarian PG in the luteolytic phase of the corpus luteum regression. Thus, our findings show that oxytocin is luteolytic in pseudopregnant rats and this action is mediated by oxytocin receptors, as it was blocked by a specific oxytocin receptor antagonist.
Assuntos
Dinoprosta/biossíntese , Ovário/metabolismo , Pseudogravidez/metabolismo , Receptores de Ocitocina/antagonistas & inibidores , Útero/metabolismo , Animais , Dinoprosta/metabolismo , Feminino , Indometacina/farmacologia , Ovário/efeitos dos fármacos , Progesterona/sangue , Antagonistas de Prostaglandina/farmacologia , Ratos , Ratos Wistar , Útero/efeitos dos fármacosRESUMO
We measured the synthesis and secretion of uterine prostaglandins E and F2 alpha (PGE and PGF2 alpha) by the uterus in vitro from pseudopregnant (psp) rats on days 5 and 10 of psp, when level of serum progesterone was high and low, respectively. We found a direct correlation between concentration of progesterone in serum and uterine content of PGE and an inverse correlation with uterine PGF2 alpha. On day 5, when progesterone was high in serum, PGE increased in tissue more than in the incubation medium, suggesting a poor liberation of this PG or utilization of PGE by the tissue. On this day, no difference was seen between content of uterine PGF2 alpha and PGF2 alpha in the incubation medium. Nevertheless, on day 10, when progesterone was lower, concentrations of both PGE and PGF2 alpha were greater (P < 0.001) in the medium than in the uterine tissue. However, PGF2 alpha in the medium was higher than PGE (P < 0.05). The results clearly demonstrate that the synthesis and release of PGE and PGF2 alpha were modified by the concentration of progesterone in the serum.
Assuntos
Dinoprosta/metabolismo , Progesterona/sangue , Prostaglandinas E/metabolismo , Pseudogravidez/metabolismo , Útero/metabolismo , Animais , Feminino , Ratos , Ratos WistarRESUMO
Significant changes in the synthesis of glycosaminoglycans occur during the transformation of stromal cells of the endometrium into decidual cells which takes place during the initial stages of pregnancy in mice. Hyaluronic acid, which is practically absent in the endometrium of virgin mice, increases dramatically on the fifth day of pregnancy, reaching its maximal concentration on day 6 followed by a 50% decrease on day 7. Changes in hyaluronic acid concentration also occur in pseudopregnant mice indicating that they are not related to the presence of the embryo in the uterus. The absolute concentration of the sulfated glycosaminoglycans, e.g., heparan sulfate, dermatan sulfate and chondroitin sulfate in the decidua did not change significantly. There was, however, a striking decrease of their biosynthesis in pregnant and pseudopregnant mice when compared to virgin mice, as shown by the use of radioactive inorganic sulfate as a precursor for the study of in vivo synthesis. A radioautographical analysis confirmed that the highest incorporation of radioactive sulfate was observed in virgin endometria when compared to pregnant ones. These studies also have shown a characteristic pattern of labeling in different regions of the endometrium that repeats itself during the different days of pregnancy.
Assuntos
Decídua/metabolismo , Glicosaminoglicanos/biossíntese , Animais , Decídua/ultraestrutura , Endométrio/metabolismo , Endométrio/ultraestrutura , Feminino , Idade Gestacional , Ácido Hialurônico/metabolismo , Camundongos , Gravidez , Pseudogravidez/metabolismo , Sulfatos/metabolismoRESUMO
The decidual reaction is characterized by the redifferentitation of the endometrial connective tissue into a tissue with epithelioid features formed by decidual cells. An ultrastructural study showed a special type of junction formed between differentiating (predecidual) cells of the mouse from day six of pseudopregnancy onward. These contacts share ultrastructural characteristics of both desmosome and adherens junctions. These junctions have usually been classified as desmosome-like. In the present work, besides the ultrastructural analysis, we investigated with light microscopy the presence of desmoplakins I and II, using streptavidin-biotin immunoperoxidase technique. We found a positive punctate staining around predecidual cells while a scarce reaction was observed in the other regions of the uterus. These results suggest that these junctions belong to the desmosome family.