Effects of anastrozole on Ki-67 antigen expression in the vaginal epithelium of female rats in persistent estrus

OBJECTIVES: Aromatase inhibitors are the first-choice drugs for the treatment of hormone sensitive breast cancer. However, in addition to the scarcity of studies, there are controversies about their effects on vaginal epithelial cell proliferation in rats, especially those in persistent estrus. METHODS: To investigate vaginal epithelial cell proliferation by Ki-67 antigen expression, persistent estrus was induced in 42 randomly selected rats. These rats were randomly divided into 2 groups: group I (control, n=21), which received 0.1 mL of propylene glycol (vehicle) daily, and group II (experimental, n=21), which received 0.5 mg/kg or 0.125 mg/day of anastrozole diluted with 0.1 mL of propylene glycol. RESULTS: Light microscopy showed a higher concentration of cells with brown Ki-67 stained nuclei in the control compared to the experimental group. The mean percentage of Ki-67 stained nuclei per 500 cells in the vaginal epithelium was 68.64±2.64 and 30.46±2.00 [mean±standard error of the mean (SEM)] in the control and experimental groups, respectively (p<0.003). CONCLUSION: This study showed that anastrozole, at the dose and treatment duration selected, significantly decreased cell proliferation in the vaginal mucosa of the rats in persistent estrus.

Comportamento de éguas após a inserção de dispositivo intravaginal impregnado com progesterona / Behavior of mares after insertion of intravaginal progesterone device / Comportamiento en yeguas después de la inserción del dispositivo intravaginal impregnado con progesterona

Considerando a escassez de estudos sobre o temperamento ou reatividade de equinos, objetivou-se com esse estudo avaliar o comportamento de éguas após a inserção do implante intravaginal de progesterona, para utilização em bovinos, por meio da observação de comportamentos individuais e coletivos. Para tanto, utilizou-se sete éguas que receberam dispositivo intravaginal impregnado com progesterona e agente luteolítico. Após a colocação dos implantes e soltura das éguas, se iniciou a observação (cinco observadores sem contato entre eles) de seus comportamentos até o tempo de 120 minutos, seguindo o modelo proposto por Heleski et al. (2002). Os resultados indicaram que durante os 120 minutos de observação todas as éguas demonstraram estar alertas, pelo menos em uma observação; que o ato de comer foi observado em todos os animais durante o período estudado e que o ato de urinar e defecar foram observados, em aproximadamente, 70 e 60%, respectivamente, dos comportamentos avaliados. Comportamentos prováveis da indicação de dor e/ou desconforto, como bater da cauda, mímica de urinar, eversão do clitóris e urinando foram observados até 65 minutos, sendo que os três primeiros cessaram aos 55 minutos. De todos os comportamentos analisados, nenhum deles foi visualizado após 65 minutos de observação. Concluiu-se que a inserção do dispositivo intravaginal impregnado com progesterona não afeta negativamente o comportamento de éguas, podendo ser utilizado sem comprometer o bem-estar desses animais.

Considering the scarcity of studies on the behavior or reactivity of horses, this study aimed to assess the behavior of mares after insertion of intravaginal progesterone implant for use in cattle, through the observation of individual and collective behavior. In order to do so, seven mares received intravaginal devices impregnated with progesterone and luteolitic agent. After the implant was placed, the mares were released, and their behavior was observed (five observers with no contact between them) for a period of 120 minutes, following the model proposed by Heleski et al. (2002). The results indicated that during the 120-minute period, all mares were alert, in at least one observation; that all animals ate during the study period, and urination and defecation were observed in approximately 70 and 60%, respectively, of the assessed behavior. Behaviors that were likely an indication of pain and/or discomfort, like hitting the tail, miming to urinate, eversion of the clitoris and urinating were observed in up to 65 minutes, with the first three symptoms ceasing after 55 minutes. None of the analyzed behaviors were viewed after 65 minutes of observation. It can be concluded that the insertion of the intravaginal device impregnated with progesterone does not adversely affect the behavior of mares, and therefore, it can be used without compromising the well-being of the animals.

Teniendo en cuenta la escasez de estudios sobre el temperamento o la reactividad de equinos, este estudio buscó evaluar el comportamiento de yeguas después de la inserción del implante de progesterona intravaginal, para su uso en ganado, a través de observación de conductas individuales y colectivas. Para ello, se utilizó siete yeguas que recibieron dispositivo intravaginal impregnado con progesterona y agente luteolítico. Después de los implantes y la liberación de las yeguas, comenzó la observación (cinco observadores sin contacto entre ellos) de sus comportamientos hasta el tiempo de 120 minutos, siguiendo el modelo propuesto por Heleski et al. (2002). Los resultados indicaron que durante los 120 minutos de observación todas las yeguas demostraron estar alertas, por lo menos en una observación; el acto de comer se observó en todos los animales durante el periodo de estudio y que el acto de la micción y la defecación, en aproximadamente, 70 y 60%, respectivamente, de los comportamientos evaluados. Comportamientos probables de indicación de dolor y/o malestar, como golpear la cola, la mímica de orinar, eversión del clítoris y orinando, observados hasta 65 minutos, siendo que los tres primeros cesaron después de 55 minutos. De todos los comportamientos analizados, ninguno de ellos se visualizó después de la observación de 65 minutos. Se concluyó que la inserción del dispositivo intravaginal impregnado con progesterona no afecta negativamente el comportamiento de yeguas, que puede ser utilizado sin comprometer el bienestar de esos animales.

Response of male mice to odours of female mice in different stages of oestrous cycle: Self-grooming behaviour and the effect of castration.

The behavioural assays were carried out in a Y-maze wherein intact, castrated and testosterone-treated male mice were exposed to oestrus and non-oestrus urine samples. The intact male mice investigated more frequently and spent more time in the Y-maze arm with oestrus urine than in that with non-oestrus urine. In contrast, the castrated mice were not attracted to oestrus urine, whereas testosterone-treated mice showed preference for oestrus urine. The rate of self-grooming was higher in intact males in case of exposure to oestrus urine while the rate was lower with respect to non-oestrus urine. However, castrated mice exhibited less self-grooming behaviour which was partially restored by testosterone treatment. The results suggest that self-grooming behaviour is an indicator of detection and discrimination of oestrus by males, and supports the androgen role in male chemosensory ability to discriminate between oestrus and non-oestrus female odours.

Detecção de estro em jaguatirica (Leopardus pardalis) utilizando citologia vaginal / Vaginal cytology for estrus detection in ocelot (Leopardus pardalis)

Utilizou-se a citologia vaginal por meio de diferentes métodos de coloração para detecção de cio em jaguatirica, Leopardus pardalis, pela estimulação hormonal exógena e pela avaliação das estruturas ovarianas por videolaparoscopia. Cinco fêmeas foram tratadas com eCG/hCG e FSH/LH a cada quatro meses pelo período de dois anos. Videolaparoscopia foi realizada após cada tratamento utilizando-se cetamina-xilazina e isoflurano. Esfregaços vaginais foram obtidos 15 dias antes e após a videolaparoscopia. As lâminas foram analisadas ao microscópio de luz quanto aos tipos celulares predominantes. Todos os animais apresentaram folículos maduros (>2mm) e corpos lúteos recentes em todas as intervenções. Não houve diferença significativa entre os resultados obtidos na mesma coloração de acordo com os tratamentos utilizados. Todas as técnicas mostraram-se eficientes na detecção de células superficiais queratinizadas anucleadas e nucleadas, intermediárias, parabasais e basais. Foi possível determinar a fase de estro em Leopardus pardalis por meio da citologia vaginal.

Vaginal cytology was evaluated for estrus detection using different stains after hormonal stimulation with exogenous gonadotrophin (eCG/hCG, FSH/LH) and videolaparoscopy for ovarian structure evaluation. Five L. pardalis were treated four times during two years. After each treatment, videolaparoscopy was performed using Ketamine-Xylazine and Isoflurane. Vaginal cytology was made 15 days before and after videolaparoscopy. Three stains were used: Diff Quick, Papanicolaou, and Shorr. The slides were analyzed for the typical cell predominance. All the animals showed mature follicles (>2mm) and recent corpus luteum in all procedures. No significative difference was observed between the results in the same stain according to the treatment eCG/hCG and FSH/LH. All stains were efficient in detection of nucleated and anuclear superficial keratinized cells; intermediated, parabasal, and basal cells. Vaginal cytology can be used for estrus detection in Leopardus pardalis.

Natural estrous cycle in normal and diabetic bitches. Basal serum total lipids and cholesterol. Serum triglycerides profiles during glucose and insulin tests

All mean basal serum, total, cholesterol and lipids (L) levels in both fasted, normal bitches and in bitches with natural diabetes mellitus (DM) at anestrous (A) and during estrous cycle were measured. Mean serum, total triglycerides (TG) concentration in these animals at the same sex, stages, fasted and during intravenous glucose (IVGTT) and insulin (ITT) tolerance tests, were studied. In normal and in diabetic bitches serum cholesterol mean basal level differed significantly; the occurrence of estrous cycles (either phase) failed to affect these levels; DM and estrous cycles did not interact significantly. As for L, the influences of group and phase of estrous cycle on this variable significantly interacted. DM raised the mean basal level of this variable, in the normal group, "sex seasons" occurrence did not affect it whereas in the diabetic animals "in seasons" (either phase) it was above as compared with that found in respective controls at A. Estrogenic and luteal phases (EP, LP) did not differ in this concern. DM raised the mean serum TG levels in the bitches in the fasting condition and also during both tests; sex cycles action is variable. During IVGTT and ITT, the mean serum TG levels were influenced by sex stages and also by time elapsed either from glucose or insulin load. Thus, in the normal group, sex cycling did not vary significantly the TG profile during IVGTT. In the normal bitches "in season" (either phase), serum TG profile at the end of ITT increased more intensely than in the dogs at sex rest. During IVGTT, in the diabetic bitches, this profile was below base line from 15 min after glucose load till the test was over. DM intensely increased the serum TG response to insulin load in the bitches at A whereas such response was moderately decreasing at the end of ITT in the diabetic bitches at LP. All these results are discussed on the bases of the current know ledge on action of endocrine and metabolic products on these variables in normal animals, and the unability of these products to explain themselves the acute, severe, diabetic chryses observed during the LP of estral cycle in diabetic bitches or even in certain normal dogs at this moment of their "season", when diabetic outset uses to occur.

Glutathione-S-transferase in rat ovary: its changes during estrous cycle and increase in its activity by estradiol-17 beta.

Glutathione-S-transferases (GSTs) are drug metabolizing and detoxification enzymes, involved in the intracellular transport and metabolism of steroid hormones. This study indicated that the enzyme was heterogeneously distributed and changed during estrous cycle. The enzyme was found to be predominantly located in the cytosolic fraction while considerable activity was also observed in the mitochondrial and microsomal fractions. The activity of GST was measured during different stages of estrous cycle, viz proestrous, estrous, metestrous and diestrous. The change in its activity was observed during different stages of estrous cycle. Estrous stage was observed to have the highest GST activity. Immature (28-29 days old) rats treated with estradiol-17 beta (5 micrograms in 0.2 ml oil/animal/day, and 10 micrograms in 0.2 ml oil/animal/day, for 3 days), ovarian GST activity seemed to increase significantly (P < 0.01). This increase in the activity and the heterogeneous distribution of GST indicates the functional role of this enzyme in the ovary under endocrine regulation.

Enhanced expression of urokinase-type plasminogen activator in the rat endometrium following induction of decidualisation.

Urokinase-type plasminogen activator(uPA) assayed in uteri of cycling and deciduoma bearing rats shows detectable levels of this enzyme in endometrium. Zymographic analysis confirms uPA of decidual tissue and, following artificial induction of decidualisation, uPA activity constantly increases in the decidualising endometrium reaching a peak on day 9 of pseudopregnancy. Endometrial uPA of nonpregnant rats does not show any significant change during estrous cycle. Results are discussed in relation to expression of this activator in endometrium of rats during morphogenesis of decidual cells.

Release of 3h-noradrenaline from the rat oviduct: changes during estrous cycle and by progesterone in vitro

La inervación noradrenérgica del oviducto parece estar bajo la influencia de una modulación hormonal. El nivel de noradrenalina (NA) es específicamente afectado, pero otros procesos como el de liberación del neurotransmisor no han sido estudiados en el oviducto de la rata. En este trabajo se estudió la liberación de 3H-noradrenalina (3H-NA) durante el ciclo estral y en particular su modificación por el efecto de la progesterona "in vitro". La liberación espontánea de 3H-NA no varía durante el ciclo pero sí la inducida por concentraciones depolarizantes de K+, que fue máxima durante el estro. La progesterona inhibió la liberación inducida de 3H-NA (K+ 80 mM) desde bajas concentraciones (5 micronM). A mayores concentraciones (50 micronM), el efecto persistió, pero, además, fue aumentada la liberación de radiactividad basal. Este efecto fue potenciado por RU-486 (antagonista sintético de la hormona). Los resultados sugieren un papel modulador para la progesterona, el cual podría relacionarse con interacciones sobre la membrana de los terminales nerviosos y no con los clásicos receptores nucleares

Uterine and placental 5-HT profile in different gestational period of albino rats.

Possible role of 5-HT in pregnancy was investigated in albino rats by biological estimation of uterine and placental 5-HT contents in different periods of gestation in normal and drug treated rats. Uterine 5-HT level increased steadily from day-1 of gestation to reach the peak on day-7; thereafter, the level continued to decline throughout the period till day-20 when 5-HT level was lowest. From day-20, a mild secondary rise started and remained persistent even after parturition. The results show that a critical level of 5-HT in early gestational period is necessary for conception. Manipulation of endogenous 5-HT do not influence duration of gestation.

Membrane Potential in Luteal Cells from Cyclic Rats: Relationship to Steroidogenic Capacity

To examine the electrophysiological properties of luteal cells and the relationship between membrane potential and luteal steroidogenic capacity, the membrane potential of luteal cells and the luteal steroidogenesis were measured under different ionic conditions following treatment with various drugs and gonadotropins. The membrane potential of luteal cells did not vary throughout the estrous cycle and was -55 +/- 1 mV. The membrane potential was highly dependent upon the external K+ concentration and was depolarized by the deprivation of external Ca2+, however) there seemed to be a lower K+ permeability in luteal membranes as the presence of 10-9 M valinomycin, a K+ ionophore Caused hyperpolarization from -55 to -91 mV. Luteal progestin production was increased in a high K+ solution but not m a Ca2+-free solution indicating that Ca2+ may be essential for steroid synthesis and/or secretion by luteal cells. Gonadotropins and ouabain induced a depolarization of the membrane potential and stimulated luteal steroidogenesis; however; prostaglandin F2alpha stimulated only steroidogenesis without any changes in membrane potential. These results suggest that the relationship between steroidogenesis and the changes in membrane potential by drugs and gonadotropins is still obscure and remains to be eluridated. The relationship between membrane potential and steroidogenesis in the luteal cell may be dependent upon the availability of intracelluar Ca2+.