Pi X J, Grattan D R
Department of Anatomy and Structural Biology, School of Medical Sciences and Neuroscience Research Centre, University of Otago, P.O. Box 913, Dunedin, New Zealand.
Brain Res Mol Brain Res. 1998 Aug 15;59(1):1-12. doi: 10.1016/s0169-328x(98)00109-0.
The prolactin receptor (PRL-R) has recently been identified in various hypothalamic nuclei of female rats. In this study, expression of both the short- and long-forms of PRL-R mRNA was investigated in 11 microdissected hypothalamic nuclei of ovariectomized, estrogen-treated rats. Specific nuclei were micropunched from 300-micrometer thick frozen coronal sections with autoclaved stainless steel needles of 300 or 500 micrometer diameter. Total RNA was extracted from the punched tissue, and the two forms of PRL-R mRNA were detected by reverse transcription polymerase chain reaction (RT-PCR) using specific primers. The RT-PCR product was verified by Southern hybridization with a digoxigenin-labelled oligonucleotide probe common to both forms. The results showed that both forms of PRL-R mRNA were expressed to varying degrees in the choroid plexus, cerebral cortex and various hypothalamic nuclei, including: ventromedial preoptic nucleus, ventrolateral preoptic nucleus, medial preoptic nucleus, suprachiasmatic nucleus, supraoptic nucleus, paraventricular hypothalamic nucleus, periventricular hypothalamic nucleus, arcuate nucleus, ventromedial hypothalamic nucleus, and median eminence. Of these brain regions, the choroid plexus expressed the highest level while the suprachiasmatic nucleus contained the lowest level of mRNA. There was no expression detected in the dorsomedial hypothalamic nucleus. The choroid plexus, supraoptic nucleus and paraventricular hypothalamic nucleus had higher levels of the short-form of the PRL-R mRNA than the long-form, whilst other hypothalamic nuclei preferentially expressed the long-form of the PRL-R mRNA. The differential expression of PRL-R gene suggests that the two forms may be differentially regulated in specific brain regions and may mediate different functions of PRL.
最近在雌性大鼠的多个下丘脑核团中发现了催乳素受体（PRL-R）。在本研究中，对去卵巢并接受雌激素处理的大鼠的11个经显微切割的下丘脑核团中PRL-R mRNA的短型和长型表达进行了研究。使用直径为300或500微米的高压灭菌不锈钢针，从300微米厚的冷冻冠状切片中显微穿孔取出特定的核团。从穿孔组织中提取总RNA，并使用特异性引物通过逆转录聚合酶链反应（RT-PCR）检测两种形式的PRL-R mRNA。RT-PCR产物通过与两种形式共有的地高辛标记寡核苷酸探针进行Southern杂交来验证。结果表明，两种形式的PRL-R mRNA在脉络丛、大脑皮层和多个下丘脑核团中均有不同程度的表达，包括：腹内侧视前核、腹外侧视前核、内侧视前核、视交叉上核、视上核、下丘脑室旁核、下丘脑室周核、弓状核、下丘脑腹内侧核和正中隆起。在这些脑区中，脉络丛中mRNA表达水平最高，而视交叉上核中含量最低。在下丘脑背内侧核中未检测到表达。脉络丛、视上核和下丘脑室旁核中PRL-R mRNA短型的水平高于长型，而其他下丘脑核团则优先表达PRL-R mRNA的长型。PRL-R基因的差异表达表明，这两种形式可能在特定脑区受到不同的调节，并可能介导PRL的不同功能。
