Regulation of LH secretion during seasonal anestrus by dopaminergic pathways in Rasa Aragonesa ewes treated or not with melatonin
نویسندگان
چکیده
منابع مشابه
Daily GnRH and LH secretion in ewes is not modified by exogenous melatonin during seasonal anestrus.
The effect of central, short-term melatonin administration on daily GnRH and LH secretion was studied in ewes during seasonal anestrus. Melatonin, in a total dose of 32 micrograms and the vehicle were perfused for 4 hours into the mediobasal hypothalamus/median eminence (MBH/ME). The mean GnRH concentration during perfusion with melatonin decreased significantly (P < 0.05), as compared to the c...
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The effect of exogenous melatonin on prostaglandin secretion was measured on Rasa Aragonesa ewes. Fourteen ewes received an 18 mg melatonin implant (M+) on 10 April and were compared with 13 control animals (without implants M-). Twenty days later, intravaginal pessaries were inserted in all animals to induce a synchronized oestrus (day 0). On day 14, ewes were injected, i.v., with 0.5 IU oxyto...
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The effect of melatonin on wool quality and thyroid function was studied. Ten ewes received a melatonin implant (M) on March 2004, and 10 ewes which were not implanted served as control (C). At monthly intervals over 12 months, f ibre length and growth were calculated, and plasma thyroxine (T4) concentrations were measured. Wool samples (~N = 2000 fibres) were collected and fibre diameter, stan...
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Two experiments were conducted to determine if propylthiouracil (PTU)-induced thyroid suppression immediately before onset of anestrus would extend the breeding season in mature ewes. In Exp. 1, twice-weekly serum concentrations of progesterone indicated that all ewes were cyclic before initiation of treatment. Beginning on d 0 (January 17), ewes received 0 (n = 4), 20 (n = 5), or 40 (n = 5) mg...
متن کاملEffective stimulation of daily LH secretion by the combined treatment with melatonin and naloxone in luteal-phase ewes.
This study was designed to test the hypothesis that melatonin would intensify daily LH release after central blockade of the opiate receptors in sexually active ewes. The intracerebroventricular infusions of vehicle (control), melatonin, naloxone and melatonin in combination with naloxone were made in ewes in the luteal phase of the estrous cycle, from 2:00 P.M. to 5:00 P.M. Blood samples were ...
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ژورنال
عنوان ژورنال: Canadian Journal of Animal Science
سال: 2003
ISSN: 0008-3984,1918-1825
DOI: 10.4141/a02-106