Patil R V, Han Z, Wax M B
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Biochem Biophys Res Commun. 1997 Sep 18;238(2):392-6. doi: 10.1006/bbrc.1997.7310.
Aquaporin 1 (AQP1), a six-transmembrane domain protein that functions as a water channel, is present in many fluid secreting and absorbing tissues such as kidney, brain, heart, and eye. It is believed that among the five known mammalian aquaporins, kidney aquaporin (AQP2) is the only water channel that is regulated by arginine vasopressin (AVP). The present data suggest that AQP1 may also be regulated by AVP. The application of AVP to Xenopus oocytes injected with AQP1 cRNA increased the membrane permeability to water. In addition, our data reveal that atrial natriuretic peptide (ANP), a peptide hormone that plays an important role in the regulation of body fluid homeostasis, blocks the AQP1-mediated increase in water permeability. Incubation with 8-bromo-cAMP or direct 8-bromo-cAMP injection into oocytes expressing AQP1 cRNA significantly increased membrane permeability to water, suggesting that stimulation of AQP1 activity by AVP may involve a cAMP-dependent mechanism. Regulation of water permeability by AVP and ANP has potential relevance to active water transport in a variety of tissues that express AQP1 including kidney, brain, and eye.
水通道蛋白1（AQP1）是一种作为水通道发挥作用的六跨膜结构域蛋白，存在于许多液体分泌和吸收组织中，如肾脏、大脑、心脏和眼睛。据信，在已知的五种哺乳动物水通道蛋白中，肾脏水通道蛋白（AQP2）是唯一受精氨酸加压素（AVP）调节的水通道。目前的数据表明，AQP1也可能受AVP调节。将AVP应用于注射了AQP1编码RNA（cRNA）的非洲爪蟾卵母细胞，可增加细胞膜对水的通透性。此外，我们的数据显示，心房利钠肽（ANP）是一种在调节体液平衡中起重要作用的肽类激素，可阻断AQP1介导的水通透性增加。用8-溴环磷酸腺苷（8-bromo-cAMP）孵育或直接将8-bromo-cAMP注射到表达AQP1 cRNA的卵母细胞中，可显著增加细胞膜对水的通透性，这表明AVP对AQP1活性的刺激可能涉及一种依赖于环磷酸腺苷（cAMP）的机制。AVP和ANP对水通透性的调节与包括肾脏、大脑和眼睛在内的多种表达AQP1的组织中的活跃水转运可能具有潜在关联。
