Spermidine Stimulates the Activity of Na+K+ ATPase Activity in the Rat Renal Medulla

1989 ◽  
Vol 77 (s21) ◽  
pp. 13P-13P
Author(s):  
J.A. Charlton ◽  
P.H. Baylis
Keyword(s):  
Atpase Activity ◽  
Renal Medulla

Renal cortical Na+-K+-ATPase activity and abundance is decreased in normal pregnant rats

1998 ◽  
Vol 275 (5) ◽  
pp. F812-F817 ◽  
Author(s):  
J. Mahaney ◽  
C. Felton ◽  
D. Taylor ◽  
W. Fleming ◽  
J. Q. Kong ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Brain Stem ◽  
Renal Cortex ◽  
Renal Medulla ◽  
Late Pregnancy ◽  
Sodium Retention ◽  
Plasma Volume Expansion ◽  
Pregnant Rats ◽  
Small Rise ◽  
Α1 Subunit

During late pregnancy, the rat undergoes massive plasma volume expansion due to cumulative renal sodium retention. In the present study, conducted in virgin, mid- ( days 11–13), and late-pregnant ( days 18–20) rats, we measured both Na+-K+-ATPase activity (by coupled enzyme assay) and abundance of the α-subunits of the Na+-K+-ATPase (by Western and slot blot analyses) in renal cortex, medulla, and brain stem. Unexpectedly, Na+-K+-ATPase in renal cortex, in both stages of pregnancy, is reduced versus the virgin, consistent with our finding of a reduced quantity of the α1-subunit. In renal medulla, there is a small rise in activity at midterm, but there is no difference in either activity or abundance of the α1-subunit in late pregnancy, when renal Na retention is maximal. In brain stem, where only α2- and α3-subunits are evident, pregnancy has no impact on enzyme activity or abundance of either isoform. In conclusion, the outcome of these experiments was unexpected in that we did not observe increased renal Na+-K+-ATPase activity in late pregnancy in the rat. In fact, in renal cortex, Na+-K+-ATPase activity and abundance are reduced. Whatever promotes net sodium retention in pregnancy must be capable of overwhelming this and several other strong natriuretic signals.

Prolactin stimulates Na+-K+-ATPase activity located in the outer renal medulla of the rat

1986 ◽  
Vol 108 (1) ◽  
pp. 95-99 ◽  
Author(s):  
C. Pippard ◽  
P. H. Baylis
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Arginine Vasopressin ◽  
Renal Medulla ◽  
Outer Medulla ◽  
Stimulatory Action ◽  
Maximal Stimulation ◽  
Human Prolactin ◽  
Cytochemical Technique ◽  
Stimulation Of

ABSTRACT The effect of rat prolactin on rat renal Na+-K+-ATPase activity was investigated by a cytochemical technique. Rat prolactin caused stimulation of Na+-K+-ATPase activity only in the outer medulla of the kidney, and not in renal cortical structures. Peak enzyme activity in cultured rat renal segments occurred after tissue had been exposed to rat prolactin for 2 min, and the time of maximal stimulation did not vary with the concentration of prolactin. There was a curvilinear response in Na +-K+-ATPase activity over the rat prolactin concentration range, 0·04–40 ng/1, but higher prolactin concentrations caused inhibition of enzyme activity. Na+-K+-ATPase response was totally blocked by specific rat prolactin antiserum. Human prolactin had no consistent effect on rat medullary Na+-K+-ATPase activity. Addition of specific tri-iodothyronine and arginine vasopressin antisera to rat prolactin was without effect, confirming that the stimulatory action of rat prolactin on Na+-K+-ATPase was not due to contamination with these hormones which are known to stimulate this enzyme. J. Endocr. (1986) 108, 95–99

Inhibition of arginine vasopressin-stimulated Na+K+ATPase activity by difluoromethyl ornithine in the rat renal medulla

1989 ◽  
Vol 121 (3) ◽  
pp. 435-439 ◽  
Author(s):  
J. A. Charlton ◽  
P. H. Baylis
Keyword(s):  
Atpase Activity ◽  
Direct Effect ◽  
Arginine Vasopressin ◽  
Culture Medium ◽  
Specific Inhibitor ◽  
Renal Medulla ◽  
Thick Ascending Limb ◽  
Medullary Thick Ascending Limb ◽  
Cytochemical Bioassay ◽  
Stimulation Of

ABSTRACT Arginine vasopressin (AVP) stimulates Na+K+ ATPase and ornithine decarboxylase (ODC) activity in the rat medullary thick ascending limb. The effect of difluoromethyl ornithine (DFMO), a specific inhibitor of ODC activity, on AVP-stimulated Na+K+ATPase activity was evaluated using a cytochemical bioassay. Peaks in Na+K+ATPase activity in cultured rat renal segments which occurred after tissue had been exposed to 1 fmol AVP/l were completely inhibited by the addition of 20 mmol DFMO/l to the culture medium containing AVP. The addition of 20 mmol DFMO/l to the culture medium containing AVP in the concentration range 0·001–10 fmol/l inhibited completely the stimulation of Na+K+ATPase activity by AVP. The response of Na+K+ATPase to increasing doses of ATP (10–40 g polypeptide/l) was not influenced by the addition of 20 mmol DFMO/l to the culture medium containing AVP, suggesting that the prevention of AVP-stimulated Na+K+ATPase activity by DFMO was not due to a direct effect on the enzyme. Journal of Endocrinology (1989) 121, 435–439

scholarly journals Spectrophotometric method for the determination of renal ouabain-sensitive H+,K+-ATPase activity.

2002 ◽  
Vol 49 (2) ◽  
pp. 515-527 ◽  
Author(s):  
Jerzy Bełtowski ◽  
Grazyna Wójcicka
Keyword(s):  
Atpase Activity ◽  
Spectrophotometric Method ◽  
Inorganic Phosphate ◽  
Microsomal Fraction ◽  
Renal Cortex ◽  
Renal Medulla ◽  
Good Reproducibility ◽  
Atpase Assay ◽  
Low Activity

The aim of this work was to develop a method for renal H+,K+-ATPase measurement based on the previously used Na+,K+-ATPase assay (Beltowski et al.: J Physiol Pharmacol.; 1998, 49: 625-37). ATPase activity was assessed by measuring the amount of inorganic phosphate liberated from ATP by isolated microsomal fraction. Both ouabain-sensitive and ouabain-resistant K+-stimulated and Na+-independent ATPase activity was detected in the renal cortex and medulla. These activities were blocked by 0.2 mM imidazolpyridine derivative, Sch 28080. The method for ouabain-sensitive H+,K+-ATPase assay is characterized by good reproducibility, linearity and recovery. In contrast, the assay for ouabain-resistant H+,K+-ATPase was unsatisfactory, probably due to low activity of this enzyme. Ouabain-sensitive H+,K+-ATPase was stimulated by K+ with Km of 0.26 +/- 0.04 mM and 0.69 +/- 0.11 mM in cortex and medulla, respectively, and was inhibited by ouabain (Ki of 2.9 +/- 0.3 microM in the renal cortex and 1.9 +/- 0.4 microM in the renal medulla) and by Sch 28080 (Ki of 1.8 +/- 0.5 microM and 2.5 +/- 0.9 microM in cortex and medulla, respectively). We found that ouabain-sensitive H+,K+-ATPase accounted for about 12% of total ouabain-sensitive activity in the Na+,K+-ATPase assay. Therefore, we suggest to use Sch 28080 during Na+,K+-ATPase measurement to block H+,K+-ATPase and improve the assay specificity. Leptin administered intraperitoneally (1 mg/kg) decreased renal medullary Na+,K+-ATPase activity by 32.1% at 1 h after injection but had no effect on H+,K+-ATPase activity suggesting that the two renal ouabain-sensitive ATPases are separately regulated.

scholarly journals Time-dependent effect of leptin on renal Na+,K+-ATPase activity.

2005 ◽  
Vol 52 (4) ◽  
pp. 803-810 ◽  
Author(s):  
Andrzej Marciniak ◽  
Anna Jamroz-Wiśniewska ◽  
Ewelina Borkowska ◽  
Jerzy Bełtowski
Keyword(s):  
Atpase Activity ◽  
Renal Cortex ◽  
Specific Inhibitor ◽  
Renal Medulla ◽  
Oxidase Inhibitor ◽  
Janus Kinases ◽  
Extracellular Signal ◽  
Time Dependent Effect ◽  
Time Periods ◽  
Diabetes And Obesity

Leptin, secreted by adipose tissue, is involved in the pathogenesis of arterial hypertension, however, the mechanisms through which leptin increases blood pressure are incompletely elucidated. We investigated the effect of leptin, administered for different time periods, on renal Na(+),K(+)-ATPase activity in the rat. Leptin was infused under anesthesia into the abdominal aorta proximally to the renal arteries for 0.5-3 h. Leptin administered at doses of 1 and 10 microg/min per kg for 30 min decreased the Na(+),K(+)-ATPase activity in the renal medulla. This effect disappeared when the hormone was infused for > or =1 h. Leptin infused for 3 h increased the Na(+),K(+)-ATPase activity in the renal cortex and medulla. The stimulatory effect was abolished by a specific inhibitor of Janus kinases (JAKs), tyrphostin AG490, as well as by an NAD(P)H oxidase inhibitor, apocynin. Leptin increased urinary excretion of hydrogen peroxide (H(2)O(2)) between 2 and 3 h of infusion. The effect of leptin on renal Na(+),K(+)-ATPase and urinary H(2)O(2) was augmented by a superoxide dismutase mimetic, tempol, and was abolished by catalase. In addition, infusion of H(2)O(2) for 30 min increased the Na(+),K(+)-ATPase activity. Inhibitors of extracellular signal regulated kinases (ERKs), PD98059 or U0126, prevented Na(+),K(+)-ATPase stimulation by leptin and H(2)O(2). These data indicate that leptin, by acting directly within the kidney, has a delayed stimulatory effect on Na(+),K(+)-ATPase, mediated by JAKs, H(2)O(2) and ERKs. This mechanism may contribute to the abnormal renal Na(+) handling in diseases associated with chronic hyperleptinemia such as diabetes and obesity.

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

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