ABSTRACT
Although an increase in VEGF expression and synthesis in association with LH has been established; it is unknown if all LH isoforms act similarly. This study evaluated the production of cAMP and VEGF among LH isoforms in two in vitro bioassays. The LH was obtained from hypophyses and the group of isoforms was isolated by chromatofocusing. cAMP production was assessed using the in vitro bioassay of HEK-293 cells and VEGF production was evaluated in granulosa cells. Immunological activity was measured with a homologous RIA. Immunoactivity and bioactivity for each isoform were compared against a standard, by estimating the IC50 and the EC50. The basic isoforms were more immunoactive than the standard. The neutral and the moderately acidic had an immunological activity similar to the standard. The acidic isoform was the least immunoreactive. cAMP production at the EC50 dose was similar among the basic isoforms, the moderately acidic and the standard; for the neutral and the acidic, the EC50 dose was higher. It was observed that compared with the control, VEGF production at the lowest LH dose was no different in the standard and each isoform. In the intermediate dose, a positive response was caused in the standard and the neutral and basic isoforms. Although the acidic isoform showed a dose-dependent response, it was not significant relative to the control. In conclusion, the basic isoform generated the greatest cAMP and VEGF production, similar to the reference standard, and the acidic the smallest.
Subject(s)
Cyclic AMP/metabolism , Luteinizing Hormone/pharmacology , Sheep/physiology , Vascular Endothelial Growth Factor A/metabolism , Animals , Female , Gene Expression Regulation/drug effects , Gene Expression Regulation/physiology , HEK293 Cells , Humans , Luteinizing Hormone/chemistry , Ovarian Follicle/cytology , Ovarian Follicle/drug effects , Pituitary Gland, Anterior , Protein Isoforms , Vascular Endothelial Growth Factor A/geneticsABSTRACT
The biological efficiency of two breeding systems for sheep in the Mexican high plateau was evaluated. A total of 300 adult and 60 replacement sheep of the Columbia breed were randomly distributed into two groups of 150 adults and 30 young ones (mean age to first birth of 18 months). Mates of 36 days with natural mount every eight months (March, November and July) were done in the first group (intensive system). In the second group (annual system), a 45-day mating was done starting on November every year. Marker males were introduced 15 days before mating in all cases, which were replaced on the first day of mating for stallions at a one male for every 20 female ratios. The physical condition of all females was evaluated every month. The animals grazed 8 to 9 hours in grasslands of alfalfa (Medicago sativa) and Orchard (Dactylis glomerata) and Rye (Lolium perenne) grasses irrigated by aspersion. Only the sheep in the intensive system received supplement during lactation and re-mating. Breeding was achieved in both systems in all seasons. The mean fertility of the three breeding of the intensive system was 83.9%; while the mean fertility of the two annual breeding was 88.3% (P < 0.05). Prolificacy was 1.12 vs 1.32 (P < 0.05) for the intensive and annual breeding, respectively; mortality at weaning was 5.3% vs 6.4% (P < 0.05), weaning rate was 0.89 vs 1.09 (P < 0.05), the number of weaned lambs per ewe in two years was 2.5 vs 2.0 and lamb weight was 55.9 vs 44.4 kg (P < 0.05), respectively. Adult ewes were superior to the young ones in all the evaluated parameters, regardless of the kind of mating (P < 0.05). Results in this study allowed to compare the biological efficiency between an intensive breeding system every eight months and an annual breeding system. They also show the possibility of mating sheep of the Columbia breed in an intensive way.
Se evaluó la eficacia biológica de dos sistemas de apareamiento en ovinos del altiplano central de México. Un total de 300 ovejas adultas y 60 de reemplazo de la raza Columbia se distribuyeron al azar en dos grupos de 150 adultas y 30 jóvenes (edad promedio al primer parto de 18 meses). En el primer grupo (sistema intensivo) se realizaron empadres de 36 días, con monta natural cada ocho meses (marzo, noviembre y julio), mientras que en el segundo grupo (sistema anual) se llevó a cabo un empadre de 45 días, iniciando en noviembre de cada año. En todos los casos, quince días antes del empadre se introdujeron machos marcadores, que en la fecha de inicio del empadre se sustituían por sementales en proporción de un macho por cada 20 hembras. Mensualmente se evaluó la condición física de todas las hembras. Los animales pastorearon de ocho a nueve horas diarias en praderas de alfalfa (Medicago sativa) y pastos orchard (Dactylis glomerata) y rye grass (Lolium perenne) irrigadas por aspersión. Solamente las ovejas del sistema intensivo recibieron complemento durante la lactancia y el reempadre. En los dos sistemas se lograron apareamientos en todas las épocas, la fertilidad en los tres empadres del sistema intensivo fue de 83.9%, mientras que el promedio de los dos empadres anuales fue de 88.3% (P < 0.05). En el mismo orden, la prolificidad fue de 1.12 vs 1.32 (P < 0.05); la mortalidad al destete, 5.3% vs 6.4% (P > 0.05); la tasa de destete, 0.89 vs 1.09 (P < 0.05); el número de corderos destetados por oveja en dos años fue de 2.5 vs 2.0, y de kg de cordero de 55.9 vs 44.4 kg (P < 0.05). Independientemente del tipo de empadre, las ovejas adultas fueron superiores a las jóvenes en todos los parámetros evaluados (P < 0.05). Los resultados de este estudio permiten comparar la eficacia biológica entre un sistema de apareamiento intensivo cada ocho meses y uno anual, también muestra la posibilidad de aparear ovejas de la raza Columbia en forma intensiva.
ABSTRACT
Apoptosis of granulosa cells during follicular atresia is preceded by oxidative stress, partly due to a drop in the antioxidant glutathione (GSH). Under oxidative stress, GSH regeneration is dependent on the adequate supply of NADPH by glucose-6-phosphate dehydrogenase (G6PD). In this study, we analyzed the changes of G6PD, GSH, and oxidative stress of granulosa cells and follicular liquid and its association with apoptosis during atresia of small (4-6 mm) and large (>6 mm) sheep antral follicles. G6PD activity was found to be higher in granulosa cells of healthy small rather than large follicles, with similar GSH concentration in both cases. During atresia, increased apoptosis and protein oxidation, as well as a drop in GSH levels, were observed in follicles of both sizes. Furthermore, the activity of G6PD decreased in atretic small follicles, but not in large ones. GSH decreased and protein oxidation increased in follicular fluid. This was dependent on the degree of atresia, whereas the changes in G6PD activity were based on the type of follicle. The higher G6PD activity in the small follicles could be related to granulosa cell proliferation, follicular growth, and a lower sensitivity to oxidative stress when compared with large follicles. The results also indicate that GSH concentration in atretic follicles depends on other factors in addition to G6PD, such as de novo synthesis or activity of other NADPH-producing enzymes. Finally, lower G6PD activity in large follicles indicating a higher susceptibility to oxidative stress associated to apoptosis progression in follicle atresia.
Subject(s)
Follicular Atresia/metabolism , Glucosephosphate Dehydrogenase/metabolism , Granulosa Cells/enzymology , Animals , Apoptosis , Cell Proliferation , Dehydroepiandrosterone/metabolism , Female , Glutathione/metabolism , Granulosa Cells/pathology , Oxidative Stress , Protein Carbonylation , SheepABSTRACT
Se evaluó el efecto de la inyección im de 3 mg de norgestomet (NG) en la inducción de atresia del folículo dominante persistente (FDP) y la formación del cuerpo lúteo (Cl) que se desarrolla después de inducir la ovulación del FDP con hCG, en vacas sincronizadas con implantes de norgestomet. Se utilizaron 11 vaquillas y 20 vacas Holstein previamente sincronizados con doble inyección de PGF2a. El día 7 del ciclo (día 0 del experimento), se les insertó un implante sc de 3 mg de norgestomet (iNG) y recibieron PGF2a; posteriormente se asignaron al azar a los siguientes tratamientos: para el tratamiento hCG (n = 8) el día tres se aplicaron 2 500 UI de hCG im; para el tratamiento hCG + NG (n = 8) el día tres se aplicaron 2 500 UI de hCG im y el día cinco recibieron 3 mg de norgestomet im; para el tratamiento NG (n = 8) el día cinco recibieron 3 mg im de norgestomet. Al grupo testigo (n = 7) se le aplicó solución salina im el día tres y el día cinco, 5 ml de aceite vegetal. El iNG se retiró nueve días después de su inserción. Diariamente, a partir de la inserción del iNG y hasta la presentación del estro, se realizaron ultrasonografías de los ovarios y se tomaron muestras sanguíneas, en las cuales se determinaron las concentraciones de progesterona. La proporción de animales en los cuales se eliminó el FDP y se promovió un recambio folicular fue similar (0.05 < P < 0.1) entre los tratamientos hCG (5/8), hCG + NG (7/8) y NG (6/7), pero fue diferente (P < 0.05) al grupo testigo, en el cual no se eliminó ningún FDP (0/7). El porcentaje de concepción fue similar (P > 0.05) entre las vacas que ovularon un folículo nuevo (66.6 por ciento; 12/18) y aquellas que ovularon el FDP (53.8 por ciento; 7/13). En el grupo hCG + NG el tratamiento con norgestomet después de la inyección de hCG evitó el desarrollo del Cl, ya que sólo una vaca de seis que ovularon tuvo niveles > 1 ng/ml de progesterona al retirar el iNG, mientras que en el grupo hCG los cinco5 animales que ovularon tuvieron niveles > 1ng/ml de progesterona (P < 0.05). Se concluye que la inyección de 3 mg de norgestomet el día cinco posterior a la inserción del iNG provocó la atresia del FDP y evitó el desarrollo del cuerpo lúteo inducido con hCG.
