Selmanoff M
Endocrinology. 1985 May;116(5):1943-52. doi: 10.1210/endo-116-5-1943.
Subcutaneous injections of ovine PRL (oPRL; 4 mg/kg) were used to study the negative feedback of PRL on its own secretion in the adult male rat. A single injection of oPRL significantly suppressed the endogenous secretion of rat PRL within 3-4 h, an effect that persisted until the oPRL was substantially cleared from the circulation some 4-6 h later. In rats injected every 8 h, rat PRL levels were suppressed for 48 h, while LH titers increased significantly at some time points, and FSH levels varied in the same direction as LH. LHRH concentrations in 10 brain structures containing cell bodies, axons, and terminal boutons were not affected by 48 h of oPRL treatment. Dopamine turnover in both medial and lateral aspects of the median eminence increased as early as 2 h after the first oPRL injection and remained elevated after 10 and 26 h of oPRL exposure. The results are consistent with the hypothesis that the tuberoinfundibular dopamine neurons mediate the negative feedback action of PRL on its own secretion. Further, under these experimental conditions, neurons projecting to both medial and lateral aspects of the median eminence are equally sensitive to elevated PRL levels.
皮下注射绵羊催乳素（oPRL；4毫克/千克）用于研究成年雄性大鼠中催乳素对其自身分泌的负反馈作用。单次注射oPRL在3至4小时内显著抑制大鼠催乳素的内源性分泌，这种作用持续到约4至6小时后oPRL从循环中基本清除。在每8小时注射一次的大鼠中，大鼠催乳素水平被抑制48小时，而促黄体生成素（LH）滴度在某些时间点显著升高，促卵泡生成素（FSH）水平与LH变化方向相同。oPRL处理48小时对10个包含细胞体、轴突和终末小体的脑结构中的促性腺激素释放激素（LHRH）浓度没有影响。早在首次注射oPRL后2小时，正中隆起内侧和外侧的多巴胺周转率就增加，并且在oPRL暴露10小时和26小时后仍保持升高。这些结果与结节漏斗多巴胺神经元介导催乳素对其自身分泌的负反馈作用这一假说一致。此外，在这些实验条件下，投射到正中隆起内侧和外侧的神经元对升高的催乳素水平同样敏感。
