Armstrong J D, Esbenshade K L, Coffey M T, Heimer E, Campbell R, Mowles T, Felix A
Department of Animal Science, North Carolina State University, Raleigh 27695-7621.
Domest Anim Endocrinol. 1990 Apr;7(2):191-8. doi: 10.1016/0739-7240(90)90025-u.
Endogenous opioid peptides mediate the effect of suckling on LH and PRL in the domestic pig. However, the role of opioids in modulating GH during lactation in swine is not known. Primiparous sows that had been immunized against GRF(1-29) conjugated to human serum albumin (GRF-HSA, n = 5) or HSA (n = 4) were used to determine changes in GH after naloxone. Treatments were imposed in all sows on day 21 of lactation when antibody titers were 9100 +/- 1629. All sows received (i.v.) naloxone (0.25 mg/kg) or saline (0.0125 ml/kg) at 15 min intervals for 165 min. Active immunization against GRF-HSA during lactation decreased (P less than 0.05) mean concentration (4.8 +/- 0.2 vs 2.6 +/- 0.1 ng/ml) and frequency (1.5 +/- 0.3 vs 0.4 +/- 0.2 peaks/4 hr). Concentrations of LH and PRL were similar in GRF-HSA and HSA immunized sows. Naloxone suppressed (P less than 0.05) GH in all sows. In HSA sows, naloxone abolished episodic release of GH and decreased average, but not basal, concentrations of GH. In sows immunized against GRF-HSA, naloxone decreased (P less than 0.05) average and basal GH but failed to decrease frequency of GH release. Naloxone failed to alter frequency of LH release. Concentrations of PRL decreased (P less than 0.05) after naloxone in all sows. In conclusion, immunization against GRF-HSA blocked most of the effect of lactation on GH. Blocking opioid receptors with naloxone decreased GH and PRL in all sows. In contrast to previous findings naloxone had no effect on LH. Opioids alter concentrations of GH through a GRF dependent and GRF independent pathway.
内源性阿片肽介导了哺乳对家猪促黄体生成素（LH）和催乳素（PRL）的影响。然而，阿片类物质在母猪泌乳期间调节生长激素（GH）方面的作用尚不清楚。使用已针对与人血清白蛋白偶联的生长激素释放因子（GRF(1 - 29)，n = 5）或人血清白蛋白（HSA，n = 4）进行免疫的初产母猪来确定纳洛酮处理后GH的变化。在泌乳第21天对所有母猪进行处理，此时抗体滴度为9100±1629。所有母猪以15分钟的间隔静脉注射纳洛酮（0.25mg/kg）或生理盐水（0.0125ml/kg），持续165分钟。泌乳期间针对GRF - HSA进行主动免疫降低了（P < 0.05）平均浓度（4.8±0.2对2.6±0.1ng/ml）和频率（1.5±0.3对0.4±0.2个峰值/4小时）。在GRF - HSA免疫母猪和HSA免疫母猪中，LH和PRL的浓度相似。纳洛酮抑制了（P < 0.05）所有母猪的GH。在HSA母猪中，纳洛酮消除了GH的脉冲式释放，并降低了GH的平均浓度，但未降低基础浓度。在针对GRF - HSA免疫的母猪中，纳洛酮降低了（P < 0.05）GH的平均浓度和基础浓度，但未能降低GH释放频率。纳洛酮未能改变LH释放频率。所有母猪在注射纳洛酮后PRL浓度均降低（P < 0.05）。总之，针对GRF - HSA进行免疫阻断了泌乳对GH的大部分影响。用纳洛酮阻断阿片受体降低了所有母猪的GH和PRL。与先前的研究结果相反，纳洛酮对LH没有影响。阿片类物质通过依赖GRF和不依赖GRF的途径改变GH浓度。
