Continuous infusion of oxytocin prevents induction of uterine oxytocin receptor and blocks luteal regression in cyclic ewes.
Continuous infusion of oxytocin prevents induction of uterine oxytocin receptor and blocks luteal regression in cyclic ewes.
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连续输注催产素可防止子宫催产素受体的诱导，并阻止周期母羊的黄体退化。
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
E. Sheldrick
中科院分区：
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作者：
A. Flint;E. Sheldrick
在发情后第13天和第21天之间连续静脉输注催产素（3微克/小时）使发情恢复延迟7天（周期长度为23.3 ± 0.6天，而对照母羊为16.6 ± 0.2天）。在较低的输注速率（0.3微克/小时）催产素延迟黄体溶解，只有2 5母羊。从第14天开始的治疗（此时黄体溶解已经开始）无效。催产素延迟黄体退化对随后周期的长度没有影响。循环孕酮浓度和黄体重量的测量表明，延长发情周期是由于防止黄体退化。在第13天开始连续催产素给药期间诱导黄体消退和行为发情，第15天给予氯前列醇（平均周期长度，17.3 +/- 0.21天）。从第13天开始连续输注催产素阻断了子宫催产素受体浓度的升高，而子宫催产素受体浓度通常在发情之前升高。在连续接受催产素（3微克/小时）的母羊中，第17天，在泪阜和泪阜间子宫内膜和子宫肌层中的平均受体浓度分别为76、36和9 fmol/mg蛋白质;在对照母羊中，这些值在发情期分别为675、638和130 fmol/mg蛋白质。接受催产素和氯前列烯醇的母羊发情当天的受体浓度与对照母羊（分别为649、852和109 fmol/mg蛋白质）无显著差异。由于氯前列烯醇（一种PGF-2 α类似物）克服了催产素的抗黄体溶解作用，因此表明连续催产素治疗可能通过下调子宫催产素受体抑制子宫产生PGF-2 α。（250字处删节）
Continuous intravenous infusion of oxytocin (3 micrograms/h) between Days 13 and 21 after oestrus delayed return to oestrus by 7 days (length of cycle 23.3 +/- 0.6 days compared to 16.6 +/- 0.2 days in control ewes). At a lower infusion rate (0.3 micrograms/h) oxytocin delayed luteolysis in only 2 of 5 ewes. Treatment from Day 14, when luteolysis had already begun, was ineffective. Delay of luteal regression by oxytocin had no effect on the length of subsequent cycles. Measurement of circulating progesterone concentrations and luteal weight showed that prolongation of the oestrous cycle was due to prevention of luteal regression. Luteal regression and behavioural oestrus were induced during continuous oxytocin administration begun on Day 13 when cloprostenol was given on Day 15 (mean cycle length, 17.3 +/- 0.21 days). Continuous oxytocin infusion from Day 13 blocked the rise in uterine oxytocin receptor concentrations which normally precedes oestrus. Mean receptor concentrations in caruncular and intercaruncular endometrium and in myometrium were 76, 36 and 9 fmol/mg protein on Day 17 in ewes receiving continuous oxytocin (3 micrograms/h); in control ewes these values were 675, 638 and 130 fmol/mg protein respectively at oestrus. Receptor concentrations on the day of oestrus in ewes receiving oxytocin and cloprostenol were not significantly different from those in control ewes (649, 852, and 109 fmol/mg protein respectively). Since cloprostenol, a PGF-2 alpha analogue, overcame the antiluteolytic action of oxytocin, it is suggested that continuous oxytocin treatment may inhibit uterine production of PGF-2 alpha, possibly by down regulating the uterine oxytocin receptor.(ABSTRACT TRUNCATED AT 250 WORDS)