Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Locally produced dopamine (DA) causes a reversible and dose-dependent inhibition in Na+-K+-ATPase activity in rat proximal tubule (PT) segments [A. Aperia, A. Bertorello, and I. Seri. Am. J. Physiol. 252 (Renal Fluid Electrolyte Physiol. 21): F32-F45, 1987.]. To examine whether this effect might be of physiological importance, rats were given normal-salt (NS) or high-salt (HS) diet for 10 days. HS diet significantly increased Na excretion but did not alter glomerular filtration rate (GFR). Benserazide (Bz), an inhibitor of the enzyme L-aromatic amino acid decarboxylase (AADC) that converts L-dopa to DA, significantly attenuated the natriuresis in HS rats but had no effect on GFR. By use of immunofluorescence (IF) studies AADC was localized to the PT. Specific AADC IF was not observed in the medulla. In AADC-positive PT segments, Na+-K+-ATPase activity was significantly lower in HS rats than in NS rats (P less than 0.001). In AADC-negative medullary thick ascending limb, Na+-K+-ATPase activity was the same in NS and HS rats. If HS rats were given Bz just before study, PT Na+-K+-ATPase activity increased significantly and was not different from Na+-K+-ATPase activity in PT segments from NS rats. Bz had no significant effect on PT Na+-K+-ATPase activity in NS rats. In PT segments from Bz-treated rats, DA inhibited Na+-K+-ATPase activity already at a dose of 10(-8) M, whereas in segments from NS rats, significant inhibition of Na+-K+-ATPase activity was not observed until DA was increased to 10(-7) M.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Proximal tubule Na+-K+-ATPase activity is inhibited during high-salt diet: evidence for DA-mediated effect. 283 7

We examined the effect of endogenous dopamine production on Pi and citrate excretion by Wistar rats. Carbidopa (20-40 mumol/kg ip) decreased dopamine, Pi, and citrate excretion within 20 min (86%, 47%, and 38%, respectively); Pi reabsorption increased 11 +/- 4% (P = 0.03). The decreases were sustained for at least 18 h. 3-Hydroxybenzylhydrazine (45 mumol/kg ip) reduced Pi excretion 24%. Benserazide (40 mumol/kg ip and 0.1 mumol/min iv) reduced dopamine excretion (94%) and blocked the effect of carbidopa on Pi and citrate excretion. In isolated perfused kidneys benserazide, carbidopa, and 3-hydroxybenzylhydrazine all decreased Pi excretion. Dopamine (1 mumol/l) added to cortical minceates reduced brush-border membrane vesicle (BBMV) 32P uptake by 8% (P < 0.02) and amiloride-inhibitable 22Na uptake by 19%. Carbidopa added to minceates increased 32P uptake by 12%. Carbidopa pretreatment increased (75%) amiloride-sensitive 22Na uptake into BBMV of rats fed a high-salt diet. Uptake was not increased into BBMV from rats fed a low-salt diet. Carbidopa increased (17%) basolateral membrane Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) gradually over 4 h. Na(+)-K(+)-ATPase did not increase in rats fed a low-phosphorous diet, but did increase when dopa was added to the diet. Thus endogenous dopamine appears to directly control Na(+)-Pi and Na+/H+ transport and secondarily alter basolateral membrane Na(+)-K(+)-ATPase.
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PMID:Endogenous renal dopamine production regulates phosphate excretion. 802 66