Daveau A, Malpaux B, Tillet Y, Roblot G, Wylde R, Chemineau P
INRA Unité de Neuroendocrinologie Sexuelle, Station de Physiologie de la Reproduction, Nouzilly, France.
J Reprod Fertil. 1994 Nov;102(2):285-92. doi: 10.1530/jrf.0.1020285.
An experiment was conducted to determine whether active immunization against melatonin could modify the perception of abrupt photoperiodic changes in ewes. Two groups each containing six intact Ile-de-France ewes were submitted to alternate periods of short days for 2.5 months and long days for 2.5 days for about 70 weeks. Three series of active immunizations against a melatonin conjugate were carried out during the first of the three long-day periods. Control ewes were actively immunized at the same time against human serum albumin. Blood samples were taken once a week throughout the experiment to measure antibody titre and affinity, and prolactin and progesterone concentrations. Sera of all treated ewes demonstrated higher antibody titres than those of control ewes. Antisera were highly specific, as evidenced by the absence of displacement of iodinated melatonin in the presence of ten melatonin metabolites. Significant effects of photoperiod and of the interaction between treatment and photoperiod on prolactin concentration were detected. Prolactin concentrations in plasma of the control ewes were high during long days and low during short days. However, in the treated ewes, with the exception of the first period of long days, prolactin concentrations were not influenced by photoperiodic changes. Ovulatory activity of control ewes, as demonstrated by progesterone measurements, was stimulated by short days and inhibited by long days. In contrast, ovulatory activity of treated ewes, after a response identical to that of control ewes after the first photoperiodic shift from long to short days, showed a complete desynchronization of ovulatory activity relative to photoperiodic changes.(ABSTRACT TRUNCATED AT 250 WORDS)
进行了一项实验，以确定对褪黑素进行主动免疫是否会改变母羊对光周期突然变化的感知。将两组各含6只未阉割的法兰西岛母羊，交替暴露于短日照2.5个月和长日照2.5个月的环境中，持续约70周。在三个长日照期的第一个期间，对褪黑素缀合物进行了三轮主动免疫。对照母羊同时对人血清白蛋白进行主动免疫。在整个实验过程中，每周采集一次血样，以测量抗体滴度和亲和力、催乳素和孕酮浓度。所有处理过的母羊血清的抗体滴度均高于对照母羊。抗血清具有高度特异性，在存在十种褪黑素代谢物的情况下，碘化褪黑素未被取代就证明了这一点。检测到光周期以及处理与光周期之间的相互作用对催乳素浓度有显著影响。对照母羊血浆中的催乳素浓度在长日照期间较高，在短日照期间较低。然而，在处理过的母羊中，除了第一个长日照期外，催乳素浓度不受光周期变化的影响。通过孕酮测量证明，对照母羊的排卵活动在短日照时受到刺激，在长日照时受到抑制。相比之下，处理过的母羊在经历了与对照母羊在第一次从长日照转变为短日照的光周期变化后相同的反应后，其排卵活动相对于光周期变化出现了完全的不同步。（摘要截选至250字）
