Do endogenous opioid peptides mediate the effects of photoperiod on release of luteinizing hormone and prolactin in ovariectomized ewes?
Do endogenous opioid peptides mediate the effects of photoperiod on release of luteinizing hormone and prolactin in ovariectomized ewes?
复制标题
内源性阿片肽是否介导光周期对卵巢切除母羊黄体生成素和催乳素释放的影响？
DOI：
10.1095/biolreprod32.4.779
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发表时间：
1985
影响因子：
3.6
通讯作者：
Jackson,GL
中科院分区：
文献类型：
--
作者：
Schillo,KK;Kuehl,D;Jackson,GL
Three experiments were done to determine if endogenous opioid peptides (EOPs) mediate the effects of photoperiod on release of luteinizing hormone (LH) and prolactin (Prl) in ovariectomized (OVX) ewes. Intravenous infusions of 0.5 naloxone X h-1 X kg body weight-1 for 3.5 h increased (P less than 0.01) mean plasma concentrations of LH and decreased (P less than 0.025) mean interpulse interval (period) of LH pulses in OVX ewes exposed to long day lengths (16L:8D). Infusions of either 1.0 or 2.5 mg morphine-SO4 X h-1 X kg-1 for 3 h increased (P less than 0.005) the period of LH pulses and increased (P less than 0.005) concentrations of Prl in OVX ewes during the breeding season. In OVX ewes exposed to long (16L:8D) or short (8L:16D) day lengths infusions of naloxone increased (P less than 0.05) mean concentrations of LH, whereas morphine decreased (P less than 0.01) mean concentrations of LH. These effects were attributed to changes in period of LH pulses (P less than 0.001). The drug X photoperiod interactions were not significant for LH parameters. Naloxone did not affect Prl release in either long- or short-day groups, but morphine increased (P less than 0.001) Prl release during long and short day lengths. The effect of morphine on Prl release was more pronounced in ewes exposed to long day lengths than in those exposed to short day lengths. In conclusion, EOPs inhibit the LH pulse generator in OVX ewes. However, it is doubtful that the EOPs mediate the steroid-independent effects of photoperiod on LH release. The results also suggest that photoperiod may influence Prl release via opiate neurons.
