Kinsley C H, Bridges R S
Harvard Medical School, Laboratory of Human Reproduction and Reproductive Biology, Boston, Massachusetts 02115.
Horm Behav. 1988 Mar;22(1):49-65. doi: 10.1016/0018-506x(88)90030-x.
Reports of elevated prolactin (Prl) levels in juvenile rats of the same strain and approximate age, together with the established role of Prl in maternal behavior in adult female rats, prompted us to examine the possible involvement of Prl in the expression of maternal-like behavior in juvenile Sprague-Dawley males and females. Experiment 1 showed that at 25 days of age both sexes exhibited a rapid onset of full maternal behavior (FMB), with males (median = 2.0 days) responding significantly more quickly than females (median = 4.0 days). Moreover, blood sampled for Prl revealed that males had significantly higher levels of circulating Prl than females, (21.0 vs 10.4 ng/ml, respectively). In Experiment 2, CB-154 treatment significantly delayed the onset of FMB in males only, causing latencies to increase to 5.0 days vs 2.0 days for Controls. Female latencies were unaffected by CB-154, 7.0 and 7.5 days for CB-154 and Control groups, respectively. A second set of both male and female juveniles was treated with either CB-154 or vehicle. CB-154 reduced Prl levels in both sexes. In the Controls, the sex difference in Prl levels (males greater than females) was again evident. In Experiment 3 juvenile males were treated with either ovine Prl (0.5 mg) + CB-154, CB-154 + Vehicle, or Vehicle + Vehicle and tested for FMB. Males treated with Prl + CB-154 required 3.0 days to exhibit FMB, significantly faster than CB-154 + Vehicle males which responded in 8.0 days. The response of Vehicle + Vehicle males was intermediate, with a latency of 5.0 days. These results provide support for the idea that Prl is involved in the maternal-like responsiveness shown by 25 day old juvenile males, but that in females a maturational factor may have prevented both heightened responsiveness to pups by 25 days of age and sensitivity to the Prl releasing mechanism(s)/Prl feedback involved in the exhibition of maternal behavior.
在相同品系且年龄相近的幼年大鼠中，有报告称催乳素（Prl）水平升高，再加上Prl在成年雌性大鼠母性行为中已确定的作用，促使我们研究Prl是否可能参与幼年斯普拉格-道利雄性和雌性大鼠类似母性行为的表达。实验1表明，在25日龄时，两性均迅速开始表现出完全母性行为（FMB），雄性（中位数 = 2.0天）的反应速度明显快于雌性（中位数 = 4.0天）。此外，采集的用于检测Prl的血液显示，雄性的循环Prl水平显著高于雌性，分别为（21.0对10.4 ng/ml）。在实验2中，CB - 154处理仅显著延迟了雄性FMB的开始，导致潜伏期增加到5.0天，而对照组为2.0天。雌性的潜伏期不受CB - 154影响，CB - 154组和对照组分别为7.0天和7.5天。另一组雄性和雌性幼鼠分别用CB - 154或赋形剂处理。CB - 154降低了两性的Prl水平。在对照组中，Prl水平的性别差异（雄性大于雌性）再次明显。在实验3中，幼年雄性分别用绵羊Prl（0.5 mg）+ CB - 154、CB - 154 +赋形剂或赋形剂+赋形剂处理，并测试其FMB。用Prl + CB - 154处理的雄性需要3.0天表现出FMB，明显快于在8.0天有反应的CB - 154 +赋形剂雄性。赋形剂+赋形剂雄性的反应处于中间水平，潜伏期为5.0天。这些结果支持了以下观点：Prl参与了25日龄幼年雄性大鼠表现出的类似母性反应，但在雌性中，一个成熟因素可能既阻止了2�日龄时对幼崽的反应增强，也阻止了对母性行为表现中涉及的Prl释放机制/Prl反馈的敏感性。
