Abstract The aim of this study was to evaluate the effects of administration of tamoxifen (Tx) and its vehicle, soybean oil (SO), during the critical period of hypothalamic sexual differentiation in ...newborn male rats in the context of gonadal histomorphology during adulthood. The animals were randomly divided into 3 groups (n = 5 each). One hour after birth, one group was treated subcutaneously with 200 μg of Tx using commercial SO (20 µL) as a vehicle, another group was treated with only 20 μL of SO, and the control group received no treatment. All rats were weighed and sacrificed by cervical dislocation on day 90 post-treatment. Testicles were removed, weighed and processed for histological evaluation. The single administration of Tx and/or SO during the critical period of sexual differentiation of the hypothalamus permanently altered testicular histomorphology, spermatogenesis, and body weight in adulthood. Alterations included vacuolization and reduction in the number of spermatogonia and Sertoli cells. The administration of Tx reduced testicular weight, the diameter and area of the seminiferous tubules, and the height of the germinal epithelium and increased the intertubular space. Soybean oil by itself reduced the number of spermatocytes and spermatids to a greater extent than Tx. There was no effect on the number of Leydig cells. The possibility that soybean oil can act as an endocrine disruptor deserves greater attention and opens the possibility for the development of new pest control methods.
Con el objetivo de evaluar la calidad de espermatozoides obtenidos de cola de epidídimo de caninos, antes y después de ser criopreservados, a 3, 24, 48 y 72 horas postmortem, se obtuvieron los ...mismos, mediante orquiectomía de caninos sacrificados, a los cuales se les realizó la disección del epidídimo y mediante flujo retrogrado con el diluyente Andersen se recolectaron los espermatozoides. A las muestras obtenidas se les evaluó la movilidad progresiva, viabilidad e integridad acrosomal antes y después de ser criopreservadas a -196°C en nitrógeno líquido. Los resultados muestran que el promedio de espermatozoides con movilidad progresiva va decreciendo significativamente (p<0.05) después de las 48 horas donde se obtiene un 70.45±5.88, 25.85±4.04 postmortem y postdescongelado, respectivamente. Para los espermatozoides vivos también va disminuyendo de manera significativa (p<0.05) obteniendo un porcentaje de 92.35±1.78 a las 3 horas, a las 24 horas de 79.95±3.48; a las 48 horas de 60.75±6.73 y a las 72 horas de 58.45±3.37. Asimismo el promedio de espermatozoides vivos al descongelar fue disminuyendo de manera significativa (p<0.05), a las 3 horas 73.30±4.64 de espermatozoides vivos, a las 24 horas 61.75±5.46, a las 48 horas 48.95±5.15 y a las 72 horas 29.75±5.8. Por último la integridad acrosomal obtuvo una disminución con diferencia significativa (p<0.05) encontrando los mejores resultados postmortem y postdescongelado hasta las 24 horas 78.05±4.57, 61.95±4.55. Se concluye que la técnica de extracción con el diluyente utilizado, así como la congelación son favorables para la recuperación de espermatozoides de cola de epidídimo de perros postmortem.
Existen diferencias anatómico-funcionales importantes entre los hipotálamos de las ratas machos y hembras, las cuales son reguladas por esteroides sexuales durante un periodo crítico del desarrollo ...hipotalámico, especialmente por el estradiol; por ejemplo, en la rata macho, el núcleo dimórfico sexual del área preóptica es seis veces más grande que en la hembra, y en el núcleo arqueado de la hembra son más abundantes las conexiones sinápticas que en los machos. En este estudio se investigaron algunas diferencias entre machos y hembras en la expresión de genes relacionados con la apoptosis, neurogénesis y sinaptogénesis en ratas de 4 h de nacidas, además se evaluó el efecto de la administración temprana de propionato de testosterona (PT) a hembras y tamoxifen (Tx) a machos, sobre el patrón de expresión del grupo de genes referidos, para lo cual se usó un análisis con microarreglos de DNA, combinado con qPCR; se encontraron diferencias en la expresión de los genes en hipotálamos de hembras y machos. En las hembras, hubo una mayor expresión de genes relacionados con la apoptosis: IL-24, Smpd3, Tpa, Pp4, Map3k1, Pge y Naca3; con la diferenciación celular, Neurod2, Zic1 y Epo y con la sinapsis y el control del ciclo celular; Syt7, Tgfbr1, Ptf1a y Cox2. También se muestra que la aplicación de Tx en los machos provocó un patrón de expresión génica similar al de las hembras testigo, mientras que el PT en las hembras no modificó la expresión de genes.
Glucosamine (GlcN)-induced insulin resistance is associated with an increase in O-linked-N-acetylglucosaminylated modified proteins (O-GlcNAcylated proteins). The role played by ...O-GlcNAc-selective-N-acetyl-beta-D-glucosaminidase (O-GlcNAcase), which removes O-N-acetyl-glucosamine residues from O-GlcNAcylated proteins, has not yet been demonstrated. We investigated whether GlcN-induced whole-body insulin resistance is related to tissue O-GlcNAcase activity and mRNA expression. GlcN (30 mumol/kg/min) or physiological saline (control) was intravenously infused into Sprague-Dawley rats for 2 h. After GlcN treatment, rats were subjected to the following: intravenous glucose tolerance test, insulin tolerance test or removal of the liver, muscle and pancreas. GlcN was found to provoke hyperglycemia compared to control (8.6 +/- 0.41 vs. 4.82 +/- 0.17 mM, p < 0.001). The insulin resistance index (HOMA-IR) increased (15.76 +/- 1.47 vs. 10.14 +/- 1.41, p < 0.001) and the beta-cell function index (HOMA-beta) diminished (182.69 +/- 22.37 vs. 592.01 +/- 103, p < 0.001). Liver glucose concentration was higher in the GlcN group than in the control group (0.37 +/- 0.04 vs. 0.24 +/- 0.038 mmol/g dry weight, p < 0.001). Insulin release index (insulin/glucose) was less in the GlcN group than in the control (2.2 +/- 0.1 vs. 8 +/- 0.8 at 120 min, p < 0.001). In the GlcN group, muscle O-GlcNAcase activity diminished (0.28 +/- 0.019 vs. 0.36 +/- 0.018 nmol of p-nitrophenyl/mg protein/min, p < 0.001), and K(m) increased (1.51 +/- 0.11 vs. 1.12 +/- 0.1 mM, p < 0.001) compared to the control. In the GlcN group, O-GlcNAcase activity/mRNA expression was altered (0.6 +/- 0.07 vs. 1 +/- 0.09 of control, p < 0.05). In conclusion, O-GlcNAcase activity is posttranslationally inhibited during GlcN-induced insulin resistance.
Existen diferencias anatómico-funcionales importantes entre los hipotálamos de las ratas machos y hembras, las cuales son reguladas por esteroides sexuales durante un periodo crítico del desarrollo ...hipotalámico, especialmente por el estradiol; por ejemplo, en la rata macho, el núcleo dimórfico sexual del área preóptica es seis veces más grande que en la hembra, y en el núcleo arqueado de la hembra son más abundantes las conexiones sinápticas que en los machos. En este estudio se investigaron algunas diferencias entre machos y hembras en la expresión de genes relacionados con la apoptosis, neurogénesis y sinaptogénesis en ratas de 4 h de nacidas, además se evaluó el efecto de la administración temprana de propionato de testosterona (PT) a hembras y tamoxifen (Tx) a machos, sobre el patrón de expresión del grupo de genes referidos, para lo cual se usó un análisis con microarreglos de DNA, combinado con qPCR; se encontraron diferencias en la expresión de los genes en hipotálamos de hembras y machos. En las hembras, hubo una mayor expresión de genes relacionados con la apoptosis: IL-24, Smpd3, Tpa, Pp4, Map3k1, Pge y Naca3; con la diferenciación celular, Neurod2, Zic1 y Epo y con la sinapsis y el control del ciclo celular; Syt7, Tgfbr1, Ptf1a y Cox2. También se muestra que la aplicación de Tx en los machos provocó un patrón de expresión génica similar al de las hembras testigo, mientras que el PT en las hembras no modificó la expresión de genes.
The Ca
2+/calmodulin (CaM) system plays important roles both in hypothalamic sexual differentiation and in the progesterone-induced facilitation of lordosis behavior in the adult rat. We recently ...showed sex-dependent differences in rat hypothalamic CaM levels, both in newborn and in adult animals. Here, we evaluated the presence of left–right hypothalamic asymmetries in CaM concentration in male and female rats, as well as the changes induced on these parameters by neonatal (1 h after birth) subcutaneous administration of tamoxifen (200 μg/rat) or testosterone (30 μg/rat). CaM was measured by RIA in each half of the hypothalamus (at 2, 6, 12, and 24 h and at 90 days after birth) in both control and treated animals. In untreated young rats (2–24 h after birth), CaM concentration was significantly higher in the right half of the hypothalamus of males, whereas in females, it was higher in the hypothalamic left half. Treatment of females with testosterone or tamoxifen to males, consistently reversed these results. In the hypothalamus of treated animals, we found higher CaM levels in the left half of males, as well as in the right half of females. In control adult females, CaM concentration was also higher in the left half of the hypothalamus, as it was in the right half of adult males. However, this asymmetry was lost after neonatal hormone manipulation. These results reinforce the role of CaM in the development of sex-related hypothalamic functions.
The aim of this study was to determine the effect of tamoxifen (Tx) and its vehicle, soybean oil (SO), during the critical period of hypothalamic sexual differentiation in newborn male rats, ...regarding gonadal histomorphology during adulthood. The animals were randomly divided into 3 groups (n = 5 each). An hour after birth, one group was treated subcutaneously with 200 μg of Tx, using commercial SO (20 uL) as a vehicle; another group was treated with only 20 μL of SO; the control group received no treatment. All rats were weighed and sacrificed by cervical dislocation on day 90 post-treatment. Testicles were removed, weighed and processed for histological evaluation. The single administration of Tx and/or SO during the critical period of sexual differentiation of the hypothalamus permanently altered testicular histomorphology, spermatogenesis, and body weight in adulthood. Alterations included vacuolization and reduction in the number of spermatogonia and Sertoli cells. The administration of Tx reduced the testicular weight, the diameter and area of the seminiferous tubules, and the height of the germinal epithelium, and increased the intertubular space. Soybean oil by itself reduced the number of spermatocytes and spermatids more than Tx did. There was no effect on the number of Leydig cells. The possibility that soybean oil can act as an endocrine disruptor deserves greater attention and opens the possibility for the development of new methods of pest control.
PDF
