Pritchett D B, Roberts J L
Proc Natl Acad Sci U S A. 1987 Aug;84(16):5545-9. doi: 10.1073/pnas.84.16.5545.
A glandular-like kallikrein enzyme, a member of a well-characterized family of specific arginyl endopeptidases that may be involved in prohormone processing, has previously been shown to be present in the anterior and neurointermediate lobes of the rat pituitary. We isolated glandular-like kallikrein cDNAs from cDNA libraries prepared from these two tissues. By nucleotide sequence, restriction endonuclease, solution hybridization/nuclease protection, and blot analyses, we showed that, of the 8-10 rat kallikrein-encoding genes, it is the true glandular kallikrein mRNA that is expressed in both pituitary lobes. RNA blot-hybridization analysis of anterior and neurointermediate lobe pituitary RNA revealed a kallikrein mRNA of approximately equal to 900 base pairs. As analyzed by blot-hybridization and solution hybridization/nuclease protection analyses, the true glandular kallikrein mRNA was present at low levels: approximately equal to 0.05% of total mRNA in both male and female neurointermediate lobes. Similar low levels of the glandular kallikrein mRNA were found in the male anterior lobe, whereas the levels were 10- to 15-fold higher in the female anterior lobe. In vivo administration of a dopamine agonist (bromocryptine) or antagonist (haloperidol) caused a decrease or increase, respectively, in the amount of true glandular kallikrein mRNA in the neurointermediate lobe of both sexes that closely paralleled changes in proopiomelanocortin mRNA levels. Bromocryptine decreased and haloperidol increased true glandular kallikrein mRNA levels in the female anterior lobe but had no effect in the male anterior lobe. Nuclear transcription run-on studies showed that the changes in mRNA were due, at least in part, to parallel effects of haloperidol on kallikrein gene transcription. Thus, these studies have demonstrated that the pituitary expresses the glandular-type member of the kallikrein gene family and that dopaminergic compounds elicit changes in kallikrein mRNA, at least in part, by modulating transcription. In the intermediate lobe, regulation of true glandular kallikrein gene expression is parallel to that of proopiomelanocortin gene expression, suggesting that the enzyme may play a physiological role in the production and/or secretion of the proopiomelanocortin peptides in this tissue.
一种腺样激肽释放酶，是一个特性明确的特异性精氨酰内肽酶家族的成员，可能参与激素原的加工过程，此前已证明它存在于大鼠垂体的前叶和神经中间叶。我们从这两个组织制备的cDNA文库中分离出腺样激肽释放酶cDNA。通过核苷酸序列、限制性内切酶、溶液杂交/核酸酶保护和印迹分析，我们发现，在8 - 10个大鼠激肽释放酶编码基因中，真正的腺性激肽释放酶mRNA在垂体的两个叶中均有表达。对垂体前叶和神经中间叶RNA进行RNA印迹杂交分析，发现一种大小约为900个碱基对的激肽释放酶mRNA。通过印迹杂交和溶液杂交/核酸酶保护分析发现，真正的腺性激肽释放酶mRNA水平较低：在雄性和雌性神经中间叶中均约占总mRNA的0.05%。在雄性垂体前叶中也发现了类似的低水平腺性激肽释放酶mRNA，而在雌性垂体前叶中其水平高10 - 15倍。体内给予多巴胺激动剂（溴隐亭）或拮抗剂（氟哌啶醇）分别导致两性神经中间叶中真正的腺性激肽释放酶mRNA量减少或增加，这与阿黑皮素原mRNA水平的变化密切平行。溴隐亭使雌性垂体前叶中真正的腺性激肽释放酶mRNA水平降低，氟哌啶醇使其升高，但对雄性垂体前叶无影响。细胞核转录连续分析表明，mRNA的变化至少部分是由于氟哌啶醇对激肽释放酶基因转录的平行作用。因此，这些研究表明垂体表达激肽释放酶基因家族的腺性成员，并且多巴胺能化合物至少部分通过调节转录引起激肽释放酶mRNA的变化。在中间叶中，真正的腺性激肽释放酶基因表达的调节与阿黑皮素原基因表达的调节平行，这表明该酶可能在该组织中阿黑皮素原肽的产生和/或分泌中发挥生理作用。
