Stimulation of Na+/K+-ATPase activity by polyamines in the rat renal medullary cells of the thick ascending limb of Henle's loop

1990 ◽  
Vol 127 (3) ◽  
pp. 377-382 ◽  
Author(s):  
J. A. Charlton ◽  
P. H. Baylis
Keyword(s):  
Atpase Activity ◽  
Arginine Vasopressin ◽  
Thick Ascending Limb ◽  
Stimulus Response ◽  
Spermine Synthase ◽  
Medullary Thick Ascending Limb ◽  
Henle's Loop ◽  
Specific Inhibitors ◽  
Stimulation Of

ABSTRACT Previous studies have indicated that ornithine decarboxylase (ODC) may be involved in the stimulation of Na+/K+-ATPase activity by arginine vasopressin (AVP) in the rat renal medullary thick ascending limb of Henle's loop. The present study was aimed at establishing the role of the polyamines, the conversion products of ODC activity, in the stimulation of Na+/K+-ATPase by AVP. Using cytochemical methods, we have demonstrated an increase in Na+/K+-ATPase activity after stimulation with putrescine, spermidine and spermine (each 1 mmol/l) for 2·5,2 and 1·5 min respectively. The specific inhibitors of spermidine and spermine synthase, bis-cyclohexylammonium sulphate and N-alkylated-1,3-diaminopropane respectively, inhibited the stimulation of Na+/K+-ATPase by AVP, this inhibition being reversed by spermine. These findings suggest that polyamines are involved in the stimulus-response coupling of the hormone-mediated response. Journal of Endocrinology (1990) 127, 377–382

Stimulation of rat renal medullary Na+/K+-ATPase by arginine vasopressin is mediated by the V2 receptor

1990 ◽  
Vol 127 (2) ◽  
pp. 213-216 ◽  
Author(s):  
J. A. Charlton ◽  
P. H. Baylis
Keyword(s):  
Atpase Activity ◽  
Arginine Vasopressin ◽  
Thick Ascending Limb ◽  
Medullary Thick Ascending Limb ◽  
Henle's Loop ◽  
Cytochemical Bioassay ◽  
V2 Receptor ◽  
Stimulation Of

ABSTRACT In previous studies, we have demonstrated that 1–10 fmol arginine vasopressin (AVP)/l maximally stimulates the activity of the enzyme Na+/K+-ATPase in the rat renal medullary thick ascending limb (MTAL) of Henle's loop after 4 or 10 min of stimulation when measured using a cytochemical bioassay. We have tested the hypothesis that this stimulation is mediated by the V2 receptor in the MTAL. A cytochemical bioassay was used to investigate the effect of specific V1 and V2/V1 antagonists and a synthetic V2 agonist [1-deamino,8-d-arginine]-vasopressin (dDAVP), on the activity of Na+/K+-ATPase. There was no effect of the V1 antagonist (1 fmol-1 μmol/l) in inhibiting the activity of Na+/K+-ATPase stimulated by 1 fmol AVP/l. In contrast, 100 pmol of the V2/V1 antagonist/l significantly (P < 0·001) inhibited the stimulation of Na+/K+-ATPase activity by 1 fmol AVP/l from 55·5±4·3 (s.e.m.) to 31·9±1·6 mean integrated extinction (MIE) after 4 min of stimulation and from 67·0±3·2 to 36·9±0·7 MIE after 10 min of stimulation. Similarly, the stimulation of Na+/K+-ATPase by 10 fmol dDAVP/l was inhibited by the V2/V1 antagonist from 55·1±1·0 to 26·1±0·5 MIE after 4 min of stimulation. We conclude that the stimulation of Na+/K+-ATPase by AVP is mediated by the V2 receptor in the rat renal MTAL. Journal of Endocrinology (1990) 127, 213–216

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

Stimulation of ornithine decarboxylase activity by arginine vasopressin in the rat medullary thick ascending limb of Henle's loop

1989 ◽  
Vol 120 (2) ◽  
pp. 195-199 ◽  
Author(s):  
J. A. Charlton ◽  
P. H. Baylis
Keyword(s):  
Ornithine Decarboxylase ◽  
Arginine Vasopressin ◽  
Specific Inhibitor ◽  
Decarboxylase Activity ◽  
Thick Ascending Limb ◽  
Medullary Thick Ascending Limb ◽  
Henle's Loop ◽  
Cytochemical Technique ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT The effect of arginine vasopressin (AVP) on rat renal ornithine decarboxylase (ODC) activity was investigated by a cytochemical technique optimized for use in the medullary thick ascending limb of Henle's loop (mTAL). Stimulation of ODC activity by AVP was confined to the mTAL. Peaks in enzyme activity in cultured rat renal segments occurred after tissue had been exposed to AVP for 3 or 8 min and these times of maximal stimulation did not change with the concentration of AVP. There was a dose-dependent response in ODC activity over the AVP concentration range 0·01–10 fmol/l. The ODC response to AVP was totally blocked by specific antiserum to AVP and reduced by 70% with the specific inhibitor to ODC, difluoromethyl ornithine. Journal of Endocrinology (1989) 120, 195–199

Role of arginine vasopressin in medullary thick ascending limb on maximal urinary concentration

1986 ◽  
Vol 251 (2) ◽  
pp. F266-F270 ◽  
Author(s):  
J. K. Kim ◽  
S. N. Summer ◽  
A. E. Erickson ◽  
R. W. Schrier
Keyword(s):  
Adenylate Cyclase ◽  
Arginine Vasopressin ◽  
Urinary Concentration ◽  
Thick Ascending Limb ◽  
Sprague Dawley ◽  
Urinary Osmolality ◽  
Medullary Thick Ascending Limb ◽  
Sprague Dawley Rats ◽  
Collecting Tubules

Two groups of Sprague-Dawley rats, Harlan (H) and Charles River (CR), were discovered in that the medullary thick ascending limb (MAL) had a profoundly different adenylate cyclase response to arginine vasopressin (AVP). Using these two groups of rats, we studied the correlation between AVP action on the MAL and maximal urinary concentration. AVP (10(-6) M) significantly stimulated adenylate cyclase in MAL of H rats (7.4 +/- 0.9 to 43.8 +/- 4.6 fmol cAMP formed X 30 min-1 X mm-1, P less than 0.001) but not in CR rats (10.3 +/- 1.4 to 12.7 +/- 2.0 fmol cAMP formed X 30 min-1 X mm-1, NS). In contrast, AVP significantly stimulated adenylate cyclase of cortical, outer and inner medullary collecting tubules from both H and CR rats. Glucagon (10(-6) M) significantly stimulated adenylate cyclase of MAL from both H and CR rats. After 48 h of fluid deprivation, urinary osmolality was significantly higher (P less than 0.001) in the H (4,504 +/- 399 mosmol/kg H2O, n = 14) than CR (2,840 +/- 176 mosmol/kg H2O, n = rats. This observation was not attributable to differences in creatinine clearance (CR, 1.30 +/- 0.24; H, 1.24 +/- 0.03 ml/min, NS, n = 4) or plasma AVP (CR, 12.75 +/- 1.44; H, 12.38 +/- 1.17 pg/ml, NS, n = 6) levels. These results therefore suggest that the action of AVP on the MAL, in addition to the effect on collecting tubules, is involved in maximal urinary concentration in rats.

Effect of metabolic acidosis and alkalosis on NEM-sensitive ATPase in rat nephron segments

1992 ◽  
Vol 262 (4) ◽  
pp. F583-F590 ◽  
Author(s):  
C. Khadouri ◽  
S. Marsy ◽  
C. Barlet-Bas ◽  
L. Cheval ◽  
A. Doucet
Keyword(s):  
Metabolic Acidosis ◽  
Atpase Activity ◽  
Thick Ascending Limb ◽  
Nephron Segments ◽  
Medullary Thick Ascending Limb ◽  
Henle's Loop ◽  
Collecting Tubule ◽  
Nephron Segment ◽  
Electrogenic Proton Pump ◽  
Chloride Treatment

An N-ethylmaleimide (NEM)-sensitive adenosinetriphosphatase (ATPase) displaying the kinetic and pharmacological properties of an electrogenic proton pump has been described in the different segments of rat nephron, where it mediates part of the active tubular proton secretion. This study was therefore designed to evaluate whether changes in urinary acidification observed during metabolic acidosis or alkalosis were associated with alterations of the activity of tubular NEM-sensitive ATPase, and if so, to localize the nephron segments responsible for these changes. Within 1 wk after the onset of ammonium chloride treatment, rats developed a metabolic acidosis, and NEM-sensitive ATPase activity was markedly increased in the medullary thick ascending limb of Henle's loop and outer medullary collecting tubule, and slightly increased in the cortical collecting tubule. Conversely, treatment with sodium bicarbonate induced a metabolic alkalosis that was accompanied by decreased NEM-sensitive ATPase activity in medullary thick ascending limb and outer medullary collecting tubule. NEM-sensitive ATPase activity was not altered in any other nephron segment tested in alkalotic and acidotic rats, i.e., the proximal tubule and the cortical thick ascending limb of Henle's loop. Changes qualitatively similar were observed as soon as 3 h after the onset of NaHCO3 or NH4Cl-loading. In the medullary collecting tubule, alterations of NEM-sensitive ATPase activity are in part due to hyperaldosteronism observed in both acidotic and alkalotic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of renal Na-K-ATPase in the rat: effect of uninephrectomy

1986 ◽  
Vol 251 (3) ◽  
pp. F506-F512 ◽  
Author(s):  
S. K. Mujais ◽  
N. A. Kurtzman
Keyword(s):  
Enzyme Activity ◽  
Adrenal Gland ◽  
Atpase Activity ◽  
Thick Ascending Limb ◽  
Medullary Thick Ascending Limb ◽  
Collecting Tubule ◽  
Pars Recta ◽  
Intact Rats ◽  
Cortical Collecting Tubule

This study has examined the temporal profile and the segmental localization along the rat nephron of the increase in Na-K-ATPase produced by uninephrectomy, and the role of the adrenal gland in the generation of the increase in enzyme activity. In adrenal-intact rats, an increase in Na-K-ATPase activity in the cortical collecting tubule (CCT) was observed at 1 wk (140 +/- 13% of sham, P less than 0.05) and sustained at 2 wk (140 +/- 8% of sham, P less than 0.05). In contrast, the enhancement of enzyme activity in the proximal convoluted tubule (PCT) was transient (at 1 wk: 164 +/- 20% of sham, P less than 0.05; and at 2 wk: 97 +/- 9% of sham, P greater than 0.5). No changes in Na-K-ATPase activity were observed in the other nephron segments studied: pars recta, medullary thick ascending limb, cortical thick ascending limb, distal convoluted tubule, and medullary collecting tubule. In adrenalectomized rats, CCT enzyme activity was lower than in adrenal-intact rats (761 +/- 84 vs. 1,984 +/- 276 pmol X mm-1 X h-1, P less than 0.001) and was not altered by uninephrectomy (849 +/- 91 pmol X mm-1 X h-1, NS). We conclude that the increase in Na-K-ATPase activity following uninephrectomy is restricted to two segments of the nephron and follows a distinctive pattern in each. In the PCT a transient enhancement in enzyme activity is observed, whereas in the CCT the increase in Na-K-ATPase is sustained and requires the presence of an intact adrenal gland.

Na-K-ATPase in nephron segments of rats developing spontaneous hypertension

1985 ◽  
Vol 249 (6) ◽  
pp. F863-F869 ◽  
Author(s):  
L. C. Garg ◽  
N. Narang ◽  
S. McArdle
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Collecting Duct ◽  
Thick Ascending Limb ◽  
Spontaneously Hypertensive ◽  
Nephron Segments ◽  
Medullary Thick Ascending Limb ◽  
Abnormal Pattern ◽  
Wistar Kyoto

Na-K-ATPase activity was determined in seven specific nephron segments of 5- and 12-wk-old spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) controls. The enzyme activity in proximal convoluted tubule (PCT) and proximal straight tubule (PST) was significantly higher in 5-wk-old SHR than in WKY. However, Na-K-ATPase activity in medullary thick ascending limb (MTAL), cortical thick ascending limb (CTAL), and distal convoluted tubule (DCT) was significantly lower in 5-wk-old SHR than in WKY. There were no significant differences in the enzyme activity in PCT, PST, MTAL, CTAL, and DCT in 12-wk-old SHR and WKY. Furthermore, there were no significant differences in Na-K-ATPase activity in collecting duct segments of 5- or 12-wk-old SHR and age-matched WKY. The possible role of the abnormal pattern of Na-K-ATPase activity in PCT, PST, MTAL, CTAL, and DCT in 5-wk-old SHR in generation of hypertension in this strain remains to be determined.

Regulation of HCO3- absorption by prostaglandin E2 and G proteins in rat medullary thick ascending limb

1996 ◽  
Vol 270 (5) ◽  
pp. F711-F717 ◽  
Author(s):  
D. W. Good ◽  
T. George
Keyword(s):  
Prostaglandin E2 ◽  
G Protein ◽  
G Proteins ◽  
Arginine Vasopressin ◽  
Thick Ascending Limb ◽  
Cyclic Monophosphate ◽  
Medullary Thick Ascending Limb ◽  
Regulatory Effects ◽  
Stimulation Of

Arginine vasopressin (AVP) inhibits HCO3- absorption (JHCO3) in the medullary thick ascending limb (MTAL) of the rat by increasing adenosine 3', 5'-cyclic monophosphate. Hyperosmolality also inhibits JHCO3 via a pathway additive to inhibition by AVP. To determine whether these regulatory effects are modulated by prostaglandin E2 (PGE2), MTAL were isolated and perfused in vitro with 25 mM HCO3- solutions (pH 7.4; 290 mosmol/kgH2O). PGE2 (10(-6) M in the bath) had no effect on JHCO3 in the absence of AVP. In contrast, with 10(-10) MAVP in the bath solution, addition of 10(-8) or 10(-6) M PGE2 to the bath increased JHCO3 from 9.7 +/- 0.8 to 14.3 +/- 1.1 pmol.min-1.mm-1 (P < 0.001). In the presence of AVP and hyperosmolality (75 mM NaCl added to perfusate and bath), PGE2 increased JHCO3 from 1.4 +/- 0.1 to 7.5 +/- 0.5 pmol.min-1.mm-1 (P < 0.005). PGE2 also stimulated JHCO3 in the presence of AVP and hypertonic urea. Cholera toxin (CTX, 10(-12)-10(-9) M in the bath) inhibited JHCO3 by 40%, and this inhibition was reversed by PGE2. PGE2 did not reverse inhibition of JHCO3 by forskolin. The stimulation of JHCO3 by PGE2 in the presence of AVP was blocked by pretreatment with pertusis toxin (PTX, 2 x 10(-11) or 10(-8) M). Neither CTX nor PTX affected inhibition of JHCO3 by hyperosmolality. These results demonstrate that PGE2 reverses inhibition of JHCO3 by AVP by acting via a PTX-sensitive G protein (presumably Gi) to inhibit AVP-stimulated adenosine 3', 5'-cyclic monophosphate production. PGE2 may act as a counterregulatory factor to maintain a stable rate of HCO3- absorption in the MTAL during antidiuresis when circulating AVP levels and medullary osmolality are elevated.

Coordinate development of oxidative enzymes and Na-K-ATPase in thick ascending limb: role of corticosteroids

1992 ◽  
Vol 263 (2) ◽  
pp. F237-F242 ◽  
Author(s):  
F. Djouadi ◽  
A. Wijkhuisen ◽  
J. Bastin
Keyword(s):  
Atpase Activity ◽  
Citrate Synthase ◽  
Oxidative Enzymes ◽  
Thick Ascending Limb ◽  
Adrenal Steroids ◽  
Postnatal Maturation ◽  
Medullary Thick Ascending Limb ◽  
Coa Transferase ◽  
Old Rats

The postnatal development of mitochondrial ATP-producing pathways and Na-K-adenosinetriphosphatase (ATPase) in the rat medullary thick ascending limb of Henle (MTAL) was studied by measuring the activities of 3-ketoacid-CoA transferase, fumarase, citrate synthase, and Na-K-ATPase in microdissected MTAL of 16, 21, and 30-day-old pups and in adults. The role of adrenal steroids in the development of these four markers was also investigated by studying 21-day-old rats adrenalectomized on day 16 and given dexamethasone or aldosterone or NaCl injections from day 16 to day 21. There were large and correlated increases in the activities of the oxidative enzymes in the MTAL of control rat kidneys between 16 and 30 days after birth; Na-K-ATPase activity in the MTAL also greatly increased during the same period. Adrenalectomy completely prevented the developmental increases in MTAL oxidative enzymes and Na-K-ATPase; dexamethasone restored the development of all four enzymes, whereas aldosterone had no effect. We conclude that the postnatal maturation of Na+ reabsorption functions in MTAL cells involves coordinated increases in the capacity to produce ATP by oxidative metabolism and in Na-K-ATPase activity. This maturation process is probably triggered by the rise in circulating glucocorticoids that occurs during the weaning period.

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