Trejter Marcin, Carraro Gianni, Rucinski Marcin, Hochol Anna, Rebuffat Piera, Nussdorfer Gastone G, Malendowicz Ludwik K
Department of Histology and Embryology, School of Medicine, Karol Marcinkowska University of Medical Sciences, PL-60781 Poznan, Poland.
Int J Mol Med. 2005 Jun;15(6):993-7.
Enucleation-induced adrenal regeneration is a classic model to investigate adrenocortical proliferation in vivo, which is dependent not only on pituitary ACTH release, but also on various other neural and endocrine signals. Arginin-vasopressin (AVP), mainly acting via V1 receptors, regulates hypothalamic-hypophyseal-adrenal axis function, acting on both its central and peripheral branches. Here, we studied whether endogenous AVP system modulates rat adrenal regeneration. Reverse transcription-polymerase chain reaction (PCR) detected only the mRNAs of V1a and V1b receptors in normal and regenerating adrenals. The expression was very low, and semi-quantitative conventional and real-time PCR showed that it was down-regulated in regenerating adrenals in relation to the time elapsed from enucleation. AVP (three subcutaneous injections 28, 16 and 4 h before sacrifice) raised metaphase index at day 5, but not at day 8 of regeneration. Unexpectedly, both V1-receptor and V2-receptor antagonists increased metaphase index at days 5 and 8 of regeneration. Neither AVP nor AVP-receptor antagonists affected plasma levels of corticosterone in rats bearing regenerating adrenals. It is concluded that AVP, acting via V1 receptors located in adrenals, exerts a stimulating effects on adrenal regeneration. Due to the down-regulation of V1-receptor expression in regenerating adrenals, this effect is very weak and is easily overcome by a tonic inhibitory action of endogenous AVP systems probably involving extra-adrenal indirect mechanisms.
摘除诱导的肾上腺再生是研究体内肾上腺皮质增殖的经典模型，这不仅依赖于垂体促肾上腺皮质激素（ACTH）的释放，还依赖于各种其他神经和内分泌信号。精氨酸加压素（AVP）主要通过V1受体发挥作用，调节下丘脑 - 垂体 - 肾上腺轴功能，作用于其中心和外周分支。在此，我们研究了内源性AVP系统是否调节大鼠肾上腺再生。逆转录 - 聚合酶链反应（PCR）仅在正常和再生肾上腺中检测到V1a和V1b受体的mRNA。其表达非常低，半定量常规PCR和实时PCR显示，与摘除后经过的时间相关，其在再生肾上腺中表达下调。AVP（在处死前28、16和4小时进行三次皮下注射）在再生第5天提高了中期指数，但在第8天未提高。出乎意料的是，V1受体拮抗剂和V2受体拮抗剂在再生的第5天和第8天均提高了中期指数。AVP和AVP受体拮抗剂均未影响再生肾上腺大鼠的血浆皮质酮水平。得出的结论是，AVP通过位于肾上腺的V1受体发挥作用，对肾上腺再生具有刺激作用。由于再生肾上腺中V1受体表达下调，这种作用非常微弱，并且很容易被内源性AVP系统可能涉及肾上腺外间接机制的强直性抑制作用所克服。
