Efecto de naxolona y morfina sobre el estradiol en la inducción de la curva de LH en ganado porcino
| Autor: | Yearwood, H., Ziecik, A.J., España España, F. |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Archivos de zootecnia 43 (161), 5-14 (1994) Helvia. Repositorio Institucional de la Universidad de Córdoba instname |
| Popis: | This study examines the role of endogenous opioids in control of the estradiol-induced luteinizing hormone (LH) surge. In the experiment 1 (Exp.1), fifteen Duroc gills were ovarieclomized at the age of 5 to 6 months and one month later challenged with estradiol benzoate (EB, 25 µg/kg i.m.) at 0 h of the experiment. Control animals (n=5) received continuos i.v. infusion of saline solution (5 ml/h) from 30 to 34 h and from 60 to 64 h preceded by single i.v- injection of 10 ml of saline in each case. The naloxone group (n=5) received naloxone (1 mg/ kg) continuously between 30 to 34 h after injection of EB, preceded by a single i.v. administration of the same amount of the drug. The morphine group (n=5) was given morphine (1 mg/kg) continuously from 60 to 64 h after EB preceded by a bolus i.v. injection of the same dose of opioid. In Exp.2 ten Duroc gills ovariectomized at the age of 6 months were prepared and challenged with EB in the same way as in Exp.1, The control group (n=5) received saline infusion from 54 to 60 h after the EB treatment while the naloxone group (n=5) received naloxone between 54 to 60 h. In Exp.1 EB alone suppressed LH values (pmol/l) from 28.1 - 36.9 to 2.2 - 4.4 during 6 to 48 h in all groups (negative feedback phase). In controls and NAL groups LH increased to 67.7±6.7 and 56.7±7.3 between 54 to 96 h (positive feedback phase), respectively (p>0.05). Hovewer, the beginning of LH surge was delayed for 6 h in naloxone given animals. LH in morphine treated gills was lower between 54 to 96 h than in controls and naloxone gills (p0,05). Sin embargo, el comienzo de la curva de LH fue retrasado por 6 horas en el grupo tratado con NAL. En las cerdas tratadas con morfina los valores de LH fueron más bajos entre las 54-96 h, comparados con el grupo control y las tratadas con NAL ( pa0,05). Estas datos muestran que mientras los péptidos-opioides endogenos pueden no estar involucrados en la acción inhibitoria del EB en la secreción de la LH, los opioides exógenos suprimen la curva de LH inducida por EB en cerdas. |
| Databáze: | OpenAIRE |
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