Gregg D W, Moss G E, Hudgens R E, Malven P V
J Anim Sci. 1986 Sep;63(3):838-47. doi: 10.2527/jas1986.633838x.
A possible role for endogenous opioid peptides (EOP) in the control of luteinizing hormone (LH) and prolactin (PRL) secretion was studied by injecting the opioid antagonist, naloxone (NAL), into postpartum ewes and cows. Twelve ewes that lambed during the fall breeding season and nursed their lambs were injected iv with NAL (1.0 mg/kg) on d 10, 14, 18, 22 and 26 postpartum. Blood samples were collected at 15-min intervals from 2 h before to 2 h after NAL, and serum concentrations of LH and PRL were quantified. Following treatment on d 10, suckling lambs were removed from 6 of the 12 ewes, creating non-suckled (NS) and suckled (S) treatment groups for subsequent study on d 14 through 26. On d 10, NAL treatment increased LH (P less than .01) but concentrations of PRL were not affected. When averaged across d 14 to 26, post-NAL concentrations of LH were greater (P less than .001) than pre-NAL concentrations (6.5 +/- .7 vs 1.9 +/- .4 ng/ml). In contrast, concentrations of PRL in the post-NAL period were lower (P less than .001) than pre-NAL concentrations (129 +/- 15 vs 89 +/- 10 ng/ml). Compared with S ewes over d 14 to 26, those in the NS group had similar pre-NAL concentrations of LH, tendencies for higher (P less than .10) post-NAL concentrations of LH, lower (P less than .001) mean serum concentrations of PRL (pre- and post-NAL) and similar pre-NAL vs post-NAL differences in serum PRL. Six suckled beef cows on d 24 to 35 were injected iv with either saline or NAL (.5 mg/kg) in a replicated crossover design. Injections of NAL increased serum concentrations of LH (P less than .05), when averaged over all 12 injections in the six cows, but serum PRL was not changed. However, three of six cows did not respond to NAL with increases in serum LH. These non-responding cows were similar to the responding cows in their pre-injection concentrations of LH and PRL, but they tended (P = .10) to have higher serum concentrations of cortisol than responding cows.
通过给产后母羊和母牛注射阿片类拮抗剂纳洛酮（NAL），研究内源性阿片肽（EOP）在促黄体生成素（LH）和催乳素（PRL）分泌控制中的可能作用。在秋季繁殖季节产羔并哺乳羔羊的12只母羊，于产后第10、14、18、22和26天静脉注射NAL（1.0 mg/kg）。在注射NAL前2小时至注射后2小时，每隔15分钟采集一次血样，并对血清中LH和PRL的浓度进行定量分析。在第10天治疗后，从12只母羊中的6只移除哺乳羔羊，形成非哺乳（NS）和哺乳（S）治疗组，用于后续第14天至26天的研究。在第10天，NAL治疗使LH升高（P＜0.01），但PRL浓度未受影响。在第14天至26天平均计算时，注射NAL后的LH浓度高于注射前（P＜0.001）（6.5±0.7对1.9±0.4 ng/ml）。相比之下，注射NAL后的PRL浓度低于注射前（P＜0.001）（129±15对89±10 ng/ml）。在第14天至26天期间，与哺乳母羊相比，非哺乳组母羊注射NAL前的LH浓度相似，注射NAL后的LH浓度有升高趋势（P＜0.10），平均血清PRL浓度（注射NAL前后）较低（P＜0.001），且血清PRL注射NAL前后的差异相似。6头处于第24天至35天的哺乳肉牛，按照重复交叉设计静脉注射生理盐水或NAL（0.5 mg/kg）。在6头牛的所有12次注射中平均计算，注射NAL使血清LH浓度升高（P＜0.05），但血清PRL未改变。然而，6头牛中有3头对NAL注射未出现血清LH升高的反应。这些无反应的牛在注射前的LH和PRL浓度与有反应的牛相似，但它们血清皮质醇浓度有高于有反应牛的趋势（P = 0.10）。
