M Takayama, H Nonoguchi, T Yang, K Machida, Y Terada, A Owada, K Tomita, F Marumo
{"title":"Acute and chronic effects of hyperosmolality on mRNA and protein expression and the activity of Na-K-ATPase in the IMCD.","authors":"M Takayama, H Nonoguchi, T Yang, K Machida, Y Terada, A Owada, K Tomita, F Marumo","doi":"10.1159/000020617","DOIUrl":null,"url":null,"abstract":"<p><p>We investigated acute and chronic effects of hyperosmolality on mRNA and protein expressions of Na-K-ATPase alpha and beta isoforms and Na-K-ATPase activity in the rat inner medullary collecting duct (IMCD). Incubation of IMCD in hypertonic medium for 30 min reduced the Na-K-ATPase activity by 50%. The Na-K-ATPase activity of dehydrated rats measured in isotonic medium was decreased, and incubation in hypertonic medium did not further decrease the activity. Incubation of IMCD in hypertonic medium for 6 h did not change alpha(1) mRNA. In contrast, dehydration decreased alpha(1) subunit mRNA and protein and beta(1) protein expressions without changing beta(1) mRNA. These data show (1) that acute hyperosmolality decreases Na-K-ATPase activity in IMCD without changing alpha(1) and beta(1) mRNA and (2) that 2 days of dehydration decreased Na-K-ATPase activity by reducing alpha(1) and beta(1) proteins. Thus, the mechanisms for the inhibition of the Na-K-ATPase activity in IMCD is different between acute and chronic exposure to hyperosmolality.</p>","PeriodicalId":12179,"journal":{"name":"Experimental nephrology","volume":"7 4","pages":"295-305"},"PeriodicalIF":0.0000,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000020617","citationCount":"4","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Experimental nephrology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1159/000020617","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 4
Abstract
We investigated acute and chronic effects of hyperosmolality on mRNA and protein expressions of Na-K-ATPase alpha and beta isoforms and Na-K-ATPase activity in the rat inner medullary collecting duct (IMCD). Incubation of IMCD in hypertonic medium for 30 min reduced the Na-K-ATPase activity by 50%. The Na-K-ATPase activity of dehydrated rats measured in isotonic medium was decreased, and incubation in hypertonic medium did not further decrease the activity. Incubation of IMCD in hypertonic medium for 6 h did not change alpha(1) mRNA. In contrast, dehydration decreased alpha(1) subunit mRNA and protein and beta(1) protein expressions without changing beta(1) mRNA. These data show (1) that acute hyperosmolality decreases Na-K-ATPase activity in IMCD without changing alpha(1) and beta(1) mRNA and (2) that 2 days of dehydration decreased Na-K-ATPase activity by reducing alpha(1) and beta(1) proteins. Thus, the mechanisms for the inhibition of the Na-K-ATPase activity in IMCD is different between acute and chronic exposure to hyperosmolality.
我们研究了高渗透压对大鼠髓内集管(IMCD) na - k - atp酶α和β亚型mRNA和蛋白表达以及na - k - atp酶活性的急性和慢性影响。IMCD在高渗培养基中培养30分钟,使na - k - atp酶活性降低50%。脱水大鼠在等渗培养基中测得na - k - atp酶活性降低,而在高渗培养基中孵育没有进一步降低活性。IMCD在高渗培养基中孵育6 h后α (1) mRNA未发生变化。相反,脱水降低了α(1)亚基mRNA、蛋白和β(1)蛋白的表达,但β (1) mRNA没有变化。这些数据表明:(1)急性高渗透压降低了IMCD中na - k - atp酶的活性,但没有改变α(1)和β (1) mRNA;(2) 2天的脱水通过降低α(1)和β(1)蛋白来降低na - k - atp酶的活性。因此,急性和慢性高渗暴露对IMCD中na - k - atp酶活性的抑制机制是不同的。