Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of 24 h of unilateral ureteral obstruction on HCO3 reabsroption and urinary acidification was studied in dogs. The postobstructed kidney (EK) had a significantly lower glomerular filtration rate and renal plasma flow than the contralateral kidney (CK). Urinary pH prior to HCO3 loading was significantly higher in the EK as was maximal HCO3 reabsorption. Saline loading depressed HCO3 reabsorption to the same degree in both kidneys. Urinary PCO2, during HCO3 loading, and during phosphate infusion, was significantly lower in the EK than the CK. Fractional Na excretion was significantly higher in the EK than the CK after deoxycorticosterone acetate administration. Na2SO4 administration enhanced acid excretion only in the CK. K excretion was significantly lower in the EK than the CK both during HCO3 loading and Na2SO4 administration. There was redistribution of cortical blood flow from the outer cortex toward the inner cortex in the EK as compared to the CK. There was no difference in plasma renin activity from both renal veins. These data demonstrate enhanced proximal H+ secretion (which is abolished by volume expansion) and impaired distal H+ secretion by the postobstructed kidney. The distal defect is likely an effect of a generalized disorder of distal transport in that both K secretion and steroid-responsive Na reabsorption were impaired in the postobstructed kidney.
 ...
PMID:Renal hydrogen ion secretion after release of unilateral ureteral obstruction. 1 Jul 40

Studies were performed to evaluate the effects of the chronic administration of furosemide on hydrogen and electrolyte excretion in dogs on a normal electrolyte diet and in the absence of electrolyte or volume depletion. Control daily excretion in five dogs averaged 64 meq for Na, 51 meq for K, 66 meq for Cl, and 17 meq for net H. Furosemide, 40 mg, in the drinking water 3 times daily was given for 4 days. On day 1 Na excretion averaged 128 meq, but thereafter was not significantly different from control levels. Over 4 days cumulative net H excretion increased 63.6 meq and plasma HCO3 rose 6.6 meq/liter. The same dogs were restudied by the same protocol except that, to obviate electrolyte depletion, NaCl and KCl were administered daily in quantities sufficient to replace urinary losses. All dogs remained in positive Na, K, and Cl balance. Body weight, hematocrit, plasma albumin, creatinine, and plasma renin activity were unchanged, indicating the absence of electrolyte or volume depletion. Nonetheless, cumulative net H excretion increased 61.2 meq and plasma HCO3 increased 4.3 meq/liter. Two adrenalectomized dogs receiving steroid replacement showed similar changes in net H excretion and plasma HCO3. These experiments suggest that chronic furosemide administration may enhance H excretion and generate alkalosis even in the absence of volume or electrolyte depletion and without increased aldosterone secretion.
 ...
PMID:Effect of chronic furosemide administration on hydrogen and sodium excretion in the dog. 1 99

Excretion of lithium in urine was studied in 2 healthy males while recumbent and while upright, either walking or standing quietly. An oral dose of 24.3 mmol of Lit was taken as three lithium carbonate tablets 13 h before clearance tests. Renal lithium clearance decreased and lithium fractional reabsorption increased while upright. Standing immersed to the neck in water, which prevents the fall in plasma volume upon changing posture from recumbent to upright, prevented the fall in renal lithium clearance as well as the rise in lithium fractional reabsorption while upright. Oral doses of guanethidine (total dose of 200 mg) or oxprenolol (total dose of 140 mg) taken to prevent high levels of sympathetic nervous system activity and plasma renin, respectively, failed to prevent the fall in renal lithium clearance or the rise in lithium fractional reabsorption upon changing posture from recumbent to upright. The findings indicate that the fall in renal lithium clearance and the rise in lithium fractional reabsorption upon changing posture from recumbent to upright is related to the fall in plasma volume but not to high levels of sympathetic nervous system activity or plasma renin activity.
 ...
PMID:The role of plasma volume, plasma renin and the sympathetic nervous system in the posture-induced decline in renal lithium clearance in man. 69 34

In patients with chronic renal failure (CRF) (CCr less than 20 ml/min), we have previously demonstrated greater rates of Na excretion (ex) when Na intake was nearly all NaHCO3 as compared to NaCl (both 200 mEq Na daily). Chloride (Cl) wasting on NaHCO3 (with severe Cl restriction) occurred, however, and may in part explain the results. To avoid Cl restriction in 6 patients with CRF (CCr 10-15 ml/min) on an estimated 10 mEq Na and Cl diet, electrolyte ex was compared on NaCl supplements of 200 mEq/day versus a daily mixture of NaHCO3 (100mEq) and NaCl (100 mEq). Periods on NaCl and the mixture lasted 4 days (order randomized) separated by re-equilibration to baseline weight (wt). Mean +/- SEM ex of Na, Cl, HCO3 mEq/day and CCr and deltawt (lbs) are compared below for the 4th day of NaCl vs NaHCO3 intake. (see article). Also there were no significant differences in K excretion, blood pressure, or plasma renin activities. Mean serum HCO3 increased from 21.2 to 25.8 mEq/l (day 1 vs 5, P less than 0.01) reflecting the net positive HCO3 balance on the mixture indicated above. Thus increments of Na intake above a fixed NaCl intake were excreted similarly whether given as NaCl or NaHCO3. Greater Na ex on NaHCO3 may depend on severe Cl restriction and/or higher serum HCO3 levels. If dietary NaCl intakes are near maximum tolerance, NaHCO3 supplementation should be accompanied by reductions in NaCl intake to maintain Na balance,
 ...
PMID:NaHCO3 and NaCl tolerance in chronic renal failure II. 83 32

Plasma renin activity (PRA) was measured in the supine position and after active upright stance in patients with endogenous depression and in a group of healthy volunteers serving as controls. In the depressed patients, PRA was further investigated in the same conditions during treatment with increasing doses of lithium carbonate. Basal PRA values were lower in depressed patients than in normal controls, particularly in the upright stance, and tended to rise gradually during lithium therapy. These findings suggest that lithium may work as a stimulant of the renin-angiotensin system, and possibly as an antidepressant, by way of producing functional activation of the norepinephrine system independent of its action on the water and electrolyte balance.
 ...
PMID:Plasma renin activity in depressed patients treated with increasing doses of lithium carbonate. 121 47

In 19 patients with unilateral renal artery stenosis and subsequent renovascular hypertension plasma renin activity (PRA), plasma concentrations of atrial natriuretic peptide (ANP), erythropoietin (Epo), H+ and HCO3-, as well as pO2 and pCO2 were assessed in renal venous blood of the 'ischaemic' and normally perfused kidney, both in arterial blood and in the inferior vena cava distally from the orifices of the renal veins. PRA and ANP were significantly elevated in venous blood of the ischaemic kidney as compared with the normally perfused kidney. In contrast to PRA and ANP, plasma concentrations of Epo were similar in blood withdrawn at all vascular sites. pO2 and pCO2, as well as blood H+ and HCO3- concentrations in venous blood of the ischaemic kidney were of the same magnitude as of the normally perfused kidney. From the results presented in this paper it follows that (i) in contrast to plasma renin activity and ANP, unilateral renal 'ischaemia' does not influence plasma concentrations of Epo in renal venous blood, and (ii) chronic haemodynamic alterations do not seem to influence Epo secretion by the kidneys.
 ...
PMID:Plasma erythropoietin concentrations in renal venous blood of patients with unilateral renovascular hypertension. 131 93

1. Renal and systemic responses to infusion of angiotensin II (1.25 and 2.5 ng min-1 kg-1 body weight) were examined in ten normal males 12 h after single doses of 750 mg of lithium carbonate, 250 mg of lithium carbonate (n = 6) or placebo. 2. Baseline mean arterial pressure [mean (SEM)] was higher after 750 mg of lithium [93.1 (1.7) versus 89.5 (1.9 mmHg, P = 0.014], and the subsequent rise in blood pressure during angiotensin II infusion was lower [8.2 (1.8) versus 12.2 (2.4) mmHg, P less than 0.02]. 3. Lithium at a dose of 750 mg increased overnight urinary sodium excretion before the study. The fall in fractional sodium excretion during angiotensin II infusion was reduced after pretreatment with 750 mg of lithium [750 mg of lithium, 2.73 (0.24) to 1.34 (0.08)%; placebo, 2.69 (0.26) to 1.01 (0.11)%; P = 0.02]. The increases in effective filtration fraction [750 mg of lithium, 5.4 (1.0)%; placebo, 8.6 (0.7)%; P less than 0.05] and total effective renal vascular resistance [750 mg of lithium, 3700 (390) dyn s cm-5; placebo 5100 (460) dyn s cm-5; P = 0.03] during angiotensin II infusion were also attenuated after 750 mg of lithium. Responses after 250 mg of lithium did not differ from those after placebo. 4. The fall in plasma renin activity and the increase in plasma aldosterone concentration during angiotensin II infusion were similar on each study day. 5. Renal responses to exogenous angiotensin II are altered after pretreatment with a 750 mg dose of lithium in normal man. This dose of lithium is not an inert marker of sodium handling.
 ...
PMID:Lithium pretreatment affects renal and systemic responses to angiotensin II infusion in normal man. 131 64

Five patients with pseudo-Bartter's syndrome from surreptitious diuretic abuse were compared with six patients with true Bartter's syndrome, diagnosed as a normotensive, hyperreninaemic, hypokalaemic metabolic alkalosis with normal urine chloride excretion, low CH2O/(CH2O+CCl) ratio during maximal water diuresis and negative urine screen for diuretics. The latter was positive for frusemide in four and for hydrochlorothiazide in the remaining pseudo-Bartter's patients. The two groups of patients did not differ as for plasma Na+, Cl-, K+, HCO3-, renin, and aldosterone, while uric acid and Mg2+ were greater in pseudo-Bartter's patients. Daily and fasting urine Na+, Cl- and K+ excretion were less in pseudo-Bartter's patients; however, there was substantial overlap of values between the two groups. Fractional distal solute reabsorption during maximal water diuresis was low in the six patients with Bartter's syndrome and in two pseudo-Bartter's patients; thus, this parameter could not be taken as a specific diagnostic marker of Bartter's syndrome. Frusemide administration, 40 mg i.v., induced a brisk increase of urine flow (11.7-21.8 ml/min), UOsm (148-186 mOsm/kg H2O) and FENa (14.6-24%) in Bartter's syndrome, but not pseudo-Bartter's patients; in all pseudo-Bartter's patients frusemide-induced changes of UOsm (13-97) and FENa (-0.5 to 10.2) were markedly less than in Bartter's syndrome patients. Frusemide resistance in pseudo-Bartter's patients was most probably related to diuretic-induced ECF volume contraction and increased proximal tubule solute reabsorption; in fact fractional lithium clearance (FELi, a marker of post-proximal solute delivery) was low in pseudo-Bartter's, but not in Bartter's syndrome patients.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Pseudo-Bartter's syndrome from surreptitious diuretic intake: differential diagnosis with true Bartter's syndrome. 132 36

1. The possible natriuretic and kaliuretic effects of a single dose of lithium, as used in lithium clearance studies, were investigated in 15 healthy subjects on fixed sodium (100 mmol/24 h) and potassium (70 mmol/24 h) intakes. Lithium carbonate (300 mg or 600 mg) or placebo tablets were administered, double-blind and in random order, midway through a 48 h urine collection (divided into six 8 h periods), at 23.00 hours. 2. During the three 24 h periods which preceded the administration of lithium or placebo (control days), rates of sodium and potassium excretion followed normal circadian patterns, but no differences in excretion rates between the 3 control days were observed. Placebo tablets did not affect excretion rates. 3. After the 300 mg dose of lithium carbonate, 24 h sodium excretion increased by approximately 17 mmol (P less than 0.05); almost all of the natriuretic effect occurred during the first two 8 h periods. No effect on potassium excretion was observed. 4. After the 600 mg dose of lithium carbonate, 24 h sodium excretion increased by approximately 48 mmol (P less than 0.001) and 24 h potassium excretion increased by approximately 19 mmol (P less than 0.01). These effects were confined to the first two 8 h periods and thus occurred before and during the usual lithium clearance period. 5. Plasma renin activity, measured in 10 subjects, increased after the 600 mg dose of lithium carbonate (P less than 0.005), but plasma concentrations of aldosterone and atrial natriuretic peptide were not significantly affected. Neither the 300 mg dose of lithium carbonate nor the placebo tablets affected hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effect of a single test dose of lithium carbonate on sodium and potassium excretion in man. 164 25

The purpose of the present studies was to examine the effect of ingestion of sodium and potassium salts of various fixed anions on blood pressure, and to assess interactions among electrolytes. In the first study, Sprague-Dawley rats fed on purified diets supplemented with Na salts of chloride, sulphate, bisulphate, carbonate and bicarbonate for 7 weeks developed higher blood pressures than rats fed on the basal diet. In a second study, rats fed on Na or K salts of HSO4, HCO3 or Cl had higher blood pressures than rats fed on the basal diet. Blood pressure measurements were not correlated with plasma volume, plasma renin activity, or plasma atrial natriuretic peptide concentrations at 7 weeks. Plasma renin activity was depressed in rats fed on supplemental Na and even more in rats fed on supplemental K salts rather than the basal diet. Generally, rats fed on supplemental Na excreted Na in urine and absorbed Na in the gut more efficiently than rats fed on the basal diet or diets supplemented with K, but the anions fed also altered Na absorption and excretion. In a third study, rats fed on diets supplemented with any Cl salt, but especially KCl, absorbed K more efficiently than those fed on the basal diet. In studies 1 and 2, the efficiency of urinary excretion of K was greatest when HCO3 and CO3 salts were fed and least when HSO4 salts were fed. Despite large variations in the efficiency of absorption and excretion of Na and K, tissue levels of the electrolytes remained constant.
 ...
PMID:Sodium, potassium and chloride utilization by rats given various inorganic anions. 183 33


1 2 3 4 5 6 Next >>