Вавиловский журнал генетики и селекции (May 2016)
Effect of vasopressin on the expression of genes for key enzymes of interstitial hyaluronan turnover and concentration ability in WAG rat kidneys
Abstract
In mammals, arginine-vasopressin (AVP) is a major hormone involved in the regulation of renal water reabsorption, acting via an increase in the osmotic permeability of the collecting duct epithelium. The AVP-induced intracellular events include, as an essential step, the trafficking of the vesicles containing the water channels, aquaporin-2, to the apical plasma membrane of the collecting duct principal cells. The interstitium of the renal inner medulla contains abundant linear negatively charged glycosaminoglycan hyaluronan (HA), which affects the water flow depending on their polymeric state. Using real-time RT-PCR, we tested the assumption that the renal hyaluronan may be involved in the longterm vasopressin effect on water reabsorption. The expression of the genes encoding hyaluronan synthase-2 (Has2) and hyaluronidase-1, 2 (Hyal1, Hyal2) in the kidneys of Wistar Albino Glaxo (WAG) was studied. Has2 mRNA content was the highest in the kidney papilla of the hydrated rats. The V2 receptor-selective vasopressin analog dDAVP (100 μg/kg bw, ip, twice a day for 2 days) induced a considerable decrease in Has2 mRNA content in the papilla with less pronounced changes in the cortex. In contrast to Has2, dDAVP treatment caused a significant increase in Hyal1 and Hyal2 mRNA content in the renal papilla. There was a good fit between Hyal1 and Hyal2 transcriptional level and changes in hyaluronidase activity in the renal tissue. It was suggested that vasopressin is able to inhibit the synthesis of hyaluronan and concomitantly promotes its degradation in the renal papilla interstitium, thereby facilitating water flow between elements of the renal countercurrent system. The implications for this effect are discussed in the context of the literature data.
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