Shimokawa N, Kato Y, Imai K, Wakabayashi K
Hormone Assay Center, Gunma University, Maebashi, Japan.
Exp Clin Endocrinol. 1990 Sep;96(1):8-14. doi: 10.1055/s-0029-1210982.
An attempt was made to clarify the relationship between the synthesis of prolactin (PRL) and its secretion during the rat estrous cycle by examining the changes in PRL messenger RNA (mRNA); PRL secretion and anterior pituitary PRL content. At various stages of the estrous cycle, pituitary and serum levels of PRL and growth hormone (GH) were measured by radioimmunoassay, while their respective mRNA contents were determined by the hybridization method. The content of pituitary PRL mRNA did not increase in parallel with the increment of the serum level of the hormone. Significant increase in PRL mRNA were observed as three peaks; 1st peak at 14:00 on the proestrus (PE) day, 2nd peak at 4:00 and 3rd peak at 22:00 on the estrus (E) day. The GH levels in the pituitary and serum, or the change in PRL mRNA appeared to be unrelated to the rat estrous cycle. From the present results, we speculate that the three peaks of PRL mRNA content might be ascribable to the direct effect of estrogen on transcription, indirect activation of transcription followed by rapid and massive secretion of PRL, and mammotrope proliferation, respectively.
通过检测催乳素（PRL）信使核糖核酸（mRNA）、PRL分泌及垂体前叶PRL含量的变化，试图阐明大鼠动情周期中PRL合成与分泌之间的关系。在动情周期的不同阶段，采用放射免疫分析法测定垂体和血清中PRL及生长激素（GH）的水平，同时用杂交法测定它们各自的mRNA含量。垂体PRL mRNA的含量并未随激素血清水平的升高而平行增加。PRL mRNA出现显著增加的三个峰值：第一个峰值出现在动情前期（PE）的14:00，第二个峰值出现在动情期（E）的4:00，第三个峰值出现在动情期的22:00。垂体和血清中的GH水平，或PRL mRNA的变化似乎与大鼠动情周期无关。根据目前的结果，我们推测PRL mRNA含量的三个峰值可能分别归因于雌激素对转录的直接作用、转录的间接激活随后PRL的快速大量分泌以及乳腺细胞增殖。
