Lux V A, Ramírez M I, Libertun C
Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina.
Proc Soc Exp Biol Med. 1988 Jul;188(3):301-7. doi: 10.3181/00379727-188-42738.
The presence and the importance of a preovulatory prolactin (PRL) peak was determined in four, natural or artificially induced, ovulatory models related to lactation in the rat. Gonadotrophin peaks were determined in the afternoon preceding ovulation in four models: postpartum ovulation (PPO), ovulation after the lactational period (AL) (natural models), ovulation after litter removal at midlactation (ML), and ovulation in lactating rats (LR) (artificially induced models). In PPO, AL, and ML rats a preovulatory PRL surge was detected, showing that its presence is a common characteristic of ovulation in the rat. Bromocriptine inhibition of PRL levels in PPO and AL rats did not modify the percentage of rats which ovulated. In contrast, this treatment was able to significantly increase ovulation percentage in ML rats. Moreover, in LR rats strong dopaminergic inhibition of PRL levels, induced by pergolide, was necessary for ovulation to take place, but if pergolide-treated rats were injected with ovine PRL ovulation was completely inhibited. These data suggest that while a PRL surge seems to be always present in natural ovulatory models, it is not essential for ovulation to take place. On the other hand, in artificially induced ovulatory models, suppression of prolactinemia is able to induce ovulation or to increase the percentage of rats which ovulated. This effect of PRL on ovulation may be direct or indirect.
在与大鼠泌乳相关的四种自然或人工诱导的排卵模型中，确定了排卵前催乳素（PRL）峰值的存在及其重要性。在四种模型中，于排卵前一天下午测定促性腺激素峰值：产后排卵（PPO）、哺乳期后排卵（AL）（自然模型）、泌乳中期去除幼崽后排卵（ML）以及泌乳大鼠排卵（LR）（人工诱导模型）。在PPO、AL和ML大鼠中检测到排卵前PRL激增，表明其存在是大鼠排卵的一个共同特征。用溴隐亭抑制PPO和AL大鼠的PRL水平，并未改变排卵大鼠的百分比。相比之下，这种处理能够显著提高ML大鼠的排卵百分比。此外，在LR大鼠中，培高利特对PRL水平的强烈多巴胺能抑制是排卵发生所必需的，但如果给用培高利特处理的大鼠注射羊PRL，排卵则会被完全抑制。这些数据表明，虽然在自然排卵模型中PRL激增似乎总是存在，但它对于排卵发生并非必不可少。另一方面，在人工诱导的排卵模型中，抑制催乳素血症能够诱导排卵或增加排卵大鼠的百分比。PRL对排卵的这种作用可能是直接的，也可能是间接的。
