RESUMEN
15-Hydroxy-prostaglandin dehydrogenase activity (PGDH) was measured in endometrium, allanto-chorion, allanto-amnion and the placenta from six cows during late gestation and six parturient cows during caesarean section. Under saturated substrate conditions PGDH activity was lower than 138 pmol g wet tissue-1 min-1 in all uterine tissues in both groups. Human placental reference samples showed a PGDH activity of 16,800 +/- 1200 pmol per g wet weight min-1 (n = 4). Under subsaturational conditions enzyme activity was demonstrated in endometrium and both fetal membranes. These results indicate that PGF2 alpha catabolism in bovine uterine tissue on day 262 and during parturition, contributes little to changing plasma PGFM concentrations.
Asunto(s)
Edad Gestacional , Hidroxiprostaglandina Deshidrogenasas/metabolismo , Trabajo de Parto/metabolismo , Preñez/metabolismo , Útero/enzimología , Alantoides/enzimología , Animales , Bovinos , Endometrio/enzimología , Femenino , Placenta/enzimología , EmbarazoRESUMEN
The influence of luteolysis on myometrial activity in late pregnant cows was studied by measuring electromyographic (EMG) activity and concentrations of progesterone and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) in maternal arterial plasma of five cows. Application of two ear implants containing progestagen at day 261 of gestation was followed by an injection of a luteolytic dose of a prostaglandin F2 alpha (PGF2 alpha) analogue (PG) on day 264. Calving was initiated by removal of the implants and a single injection of 5 mg flumethasone on day 270. All calves were born alive at a mean interval of 36 h. After 4 h of hyperactivity immediately following the injection of PG, myometrial activity was almost completely absent for 20 h; before luteolysis the total duration of EMG activity was 7.21 +/- 0.31 min h-1 (mean +/- SEM), during the 4 h after PG 23.61 +/- 3.40 min h-1, and during inhibition 2.70 +/- 0.87 min h-1. After the last period, EMG activity recurred and reached values of 14.52 +/- 3.07 and 11.17 +/- 2.87 min h-1, on days 265 and 269, respectively. Concentrations of progesterone in maternal plasma decreased from 4.17 to 1.14 ng ml-1 within 12 h after PG, whereas concentrations of PGFM in plasma remained low, varying from 15 to 30 pg ml-1. After removal of the implants and injection of flumethasone on day 270, EMG activity increased without an inhibitory phase and reached maximum values around the time of expulsion of the calves.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Bovinos/fisiología , Luteólisis/fisiología , Miometrio/fisiología , Preñez/fisiología , Pregnenodionas/farmacología , Congéneres de la Progesterona/farmacología , Contracción Uterina/efectos de los fármacos , Animales , Implantes de Medicamentos , Electromiografía , Femenino , Luteólisis/efectos de los fármacos , Miometrio/efectos de los fármacos , Embarazo , Progesterona/sangre , Prostaglandinas F Sintéticas/farmacologíaRESUMEN
One hundred and forty-six Dutch cross Friesian cows were selected from a local slaughterhouse and synchronised with norgestomet. The 134 cows with a normal progesterone pattern after the removal of the norgestomet implant were treated intramuscularly with 3000 iu pregnant mare's serum gonadotrophin (PMSG) on day 10 followed by 22.5 mg prostaglandin 48 hours later. Blood samples were collected daily and at hourly intervals from 30 to 54 hours after the prostaglandin. The 113 cows with a pre-ovulatory peak of luteinising hormone (LH) were divided into three groups: 37 control cows (group 1) received a placebo six hours after the LH peak; 42 cows (group 2) received anti-PMSG six hours after the LH peak and 34 cows (group 3) received anti-PMSG 18 hours after the LH peak. All the cows were inseminated 10 hours after the LH peak. Six or seven days after insemination the cows were slaughtered and the embryos were evaluated after flushing the ovaries, and the numbers of corpora lutea, cysts and follicles on the donor ovaries were counted. Treatment with anti-PMSG had no significant effect on the numbers of corpora lutea or the numbers of embryos compared with the control group. The mean (+/- sem) numbers of corpora lutea were 14.7 +/- 1.4, 16.3 +/- 1.4 and 16.6 +/- 1.4 for groups 1, 2 and 3, respectively. The numbers of transferable embryos were 3.5 +/- 0.6, 4.1 +/- 0.7 and 5.0 +/- 0.7 for groups 1, 2 and 3, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Bovinos/fisiología , Transferencia de Embrión/veterinaria , Gonadotropinas Equinas/inmunología , Superovulación , Animales , Anticuerpos Monoclonales/inmunología , Sincronización del Estro , Femenino , Gonadotropinas Equinas/sangre , Inseminación Artificial/veterinaria , Hormona Luteinizante/sangre , Embarazo , Pregnenodionas , Progesterona/sangre , Congéneres de la Progesterona , Prostaglandinas F Sintéticas , Distribución AleatoriaRESUMEN
To investigate whether calving could be controlled by the withdrawal of progestogen implants from cows treated near term with prostaglandin three cows (group 1) received an intramuscular injection of 5 mg flumethasone on day 270 of pregnancy, and four cows (group 2) and three cows (group 3) received implants containing 3 mg norgestomet in both ears on day 262 of gestation and were treated with a prostaglandin F2 alpha analogue on day 264. On day 270 the implants were removed and at the same time the cows of group 3 were treated with 5 mg flumethasone. Jugular blood samples were taken daily to estimate progesterone concentrations in the plasma. Luteolysis was achieved by the injection of prostaglandin, as judged by the decrease in plasma progesterone concentration in the cows of groups 2 and 3 on day 264. Pregnancy was maintained in these cows until after the removal of the norgestomet implants. The interval from the removal of the implants and, or, the injection of flumethasone on day 270 until the onset of second stage labour ranged from 36 to 47 hours and the mean intervals for the three groups were not significantly different. In all the cows except one from group 3 the dilatation of the cervix and vagina and the softening of the pelvic ligaments appeared normal at calving. It is concluded that calving near term can be synchronised by a progestogen in the absence of a corpus luteum.
Asunto(s)
Bovinos/fisiología , Dinoprost/farmacología , Trabajo de Parto/efectos de los fármacos , Preñez/efectos de los fármacos , Pregnenodionas/farmacología , Animales , Cuerpo Lúteo/efectos de los fármacos , Implantes de Medicamentos , Femenino , Flumetasona/farmacología , Trabajo de Parto Inducido/veterinaria , Embarazo , Pregnenodionas/administración & dosificación , Progesterona/sangre , Congéneres de la Progesterona/administración & dosificación , Congéneres de la Progesterona/farmacologíaRESUMEN
The temporal relationship among changes of the concentrations of the 13,14-dihydro-15-keto metabolite of prostaglandin F2 alpha (PGFM), estrone (E1) and estrone sulphate (E1S) in maternal arterial plasma (MP) and amniotic fluid (AF), the prepartum progesterone (P4) decline in MP, and the evolution of uterine electromyographic (EMG) activity was investigated in 6 cows. Calving was induced by a single i.m. injection of 5 mg flumethason on Day 270 of gestation. The period under investigation was subdivided into four consecutive periods: Period 1 covered the last 2 days before flumethason treatment; Period 2 (mean +/- SEM duration: 16.1 +/- 2.5 h), Period 3 (8.8 +/- 1.1 h), and Period 4 (13.0 +/- 1.5 h) together included the interval between injection and the onset of the expulsive stage of induced parturition. Each was defined by its pattern of uterine EMG activity. During Periods 1 and 2, this activity occurred in long episodes (2-20 min; contractures) at a similar mean (+/- SEM) frequency (0.51 +/- 0.14/h and 0.42 +/- 0.07/h, respectively). No significant differences in hormonal concentrations in MP and AF between these two periods were detected. During Period 3, contractures nearly disappeared (freq: 0.09 +/- 0.05/h), and in MP mean P4 levels were significantly lower and PGFM levels were significantly higher than before. Mean PGFM concentrations in AF were not significantly changed during Period 3. Finally, during Period 4, EMG activity reappeared and a parturient EMG pattern gradually evolved in the presence of a further significant decline of P4 levels and significant increase of PGFM concentrations in MP.(ABSTRACT TRUNCATED AT 250 WORDS)