Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0235394 (wasting)
 8,040 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of renal potassium wasting in renal tubular acidosis associated with the Fanconi syndrome (type 2 RTA) was investigated in 10 patients, each of whom had impaired proximal renal tubular reabsorption of bicarbonate as judged from a greater than 15-20% reduction of renal tubular bicarbonate reabsorption (THCO(3) (-)) at normal plasma bicarbonate concentrations. When the plasma bicarbonate concentration ([HCO(3) (-)]p) was experimentally increased to normal levels in three patients with a fractional potassium excretion (C(K)/C(in)) of less than 1.0 during acidosis, C(K)/C(in) and urinary potassium excretion (U(K)V/C(in)) increased strikingly and concurrently with a striking increase in urinary sodium (U(Na)V/C(in)) and bicarbonate (U(HCO3-)V/C(in)) excretion. When [HCO(3) (-)]p was increased to normal levels in two patients with a C(K)/C(in) of greater than 1.0 during acidosis and in whom U(Na)V/C(in) and U(HCO3-)V/C(in) were already markedly increased, C(K)/C(in) did not increase further. When [HCO(3) (-)]p was decreased to subnormal levels in a patient given ammonium chloride, U(K)V/C(in), C(K)/C(in), and U(HCO3-)V/C(in) decreased concurrently. In the six patients in whom [HCO(3) (-)]p was maintained at normal levels (oral alkali therapy) for 2 months or longer, C(K)/C(in) was directly related to the urinary excretion rates of sodium and bicarbonate, hence was directly related to the magnitude of reduction of THCO(3) (-) at normal [HCO(3) (-)]p; C(K)/C(in) was greater than 0.55 in all six patients and greater than 1.0 in four. In eight patients with classic RTA (type 1 RTA), proximal renal tubular reabsorption of bicarbonate was largely intact as judged from a trivial reduction of THCO(3) (-) at normal [HCO(3) (-)]p. When [HCO(3) (-)]p was either increased from subnormal to normal levels, or decreased from normal to subnormal levels, U(HCO3-)V/C(in) remained essentially constant, and U(K)V/C(in) did not change significantly. When correction of acidosis was sustained, U(HCO3-)V/C(in) remained a trivial fraction of that filtered, and C(K)/C(in) was consistently less than 0.55. These results provide evidence that renal potassium wasting in type 2 RTA is physiologically separable from that in type 1 RTA and in part the result of a reduction in the rate at which the proximal tubule reabsorbs bicarbonate and the distal delivery of supernormal amounts of sodium bicarbonate. With an increased stimulus to distal sodium reabsorption, indicated by the finding of hyperaldosteronism, delivery to the distal nephron of supernormal amounts of sodium with the relatively impermeant bicarbonate anion would be expected to increase intraluminal negativity in the distal nephron, and as a consequence, increase potassium secretion and promote renal potassium wasting.
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PMID:On the mechanism of renal potassium wasting in renal tubular acidosis associated with the Fanconi syndrome (type 2 RTA). 510 Dec 97

Monitoring of urinary enzymuria has been utilized to detect allograft dysfunction after pancreas transplantation with pancreaticocystostomy. In addition, pharmacologic exocrine suppression has been advocated to minimize bicarbonate and protein wasting. Ensuring the validity of these approaches requires controlling both for immunologic alterations in transplant function and for the renal excretion of amylase, bicarbonate, and protein. Toward this end, adult mongrel dogs were divided into two groups. Group A animals underwent distal pancreatectomy alone, and group B animals underwent distal pancreatectomy with autotransplantation and pancreaticocystostomy. In each group, amylase, bicarbonate, and protein output were determined over a 5-hour period in the basal state, during a continuous infusion of octapeptide-cholecystokinin (OP-CCK) at 125 ng/kg/hour, and during a continuous infusion of OP-CCK (125 ng/kg/hour) plus a bolus injection of one clinical unit of secretion per kilogram. Bicarbonate output was not significantly different in the groups with and without autografts. Compared to nonautograft experiments, a statistically significant increase in amylase output was demonstrated in the autograft animals. An increase in protein output was also demonstrated in the autograft experiments, and this increase was statistically significant in the OP-CCK group and the OP-CCK and secretin group. In addition, compared to basal autograft secretion, OP-CCK and OP-CCK plus secretin stimulation resulted in a sustained and significant increase in urinary amylase and protein secretion, indicating preserved sensitivity of the denervated pancreas to exogenous hormones. These results indicate that the canine segmental pancreatic autograft model with pancreaticocystostomy is a suitable model to identify agents associated with exocrine inhibition after transplantation.
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PMID:A laboratory model for evaluation of posttransplant pancreatic exocrine secretion. 768 Aug 98

Ten stable, normocalcemic renal transplant patients with good allograft function, hyperparathyroidism, and variable hypophosphatemia were treated for 2 to 9 months with oral calcium carbonate and replacement doses of vitamin D analogues. Parathyroid hormone levels (PTH) and renal phosphate wasting were not autonomous or fixed but decreased with therapy. Although serum 1-25(OH)2D3 levels could be shown to rise appropriately during oral vitamin D therapy and fall afterwards, a separate study in a larger group of patients showed no effect of elevated parathyroid hormone or hypophosphatemia to increase endogenous 1-25(OH)2D3 levels. Some 42% of patients with elevated carboxy-terminal PTH, had elevated N-terminal PTH, which was closely associated with more severe phosphate wasting. Aggressive oral calcium and vitamin D supplementation in certain normocalcemic renal transplant patients may decrease endogenous PTH levels, improve hypophosphatemia, and provide a physiologic increase in levels of 1-25(OH)2D3.
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PMID:Effect of daily oral vitamin D and calcium therapy, hypophosphatemia, and endogenous 1-25 dihydroxycholecalciferol on parathyroid hormone and phosphate wasting in renal transplant recipients. 821 5

Ischemic renal injury is associated with changes in the expression of a number of genes. Although pH regulation is undoubtedly important during the recovery from ischemia, the expression of acid-base transporters during acute ischemic renal failure has not been studied. In the present study, levels of mRNA encoding the colonic H+-K+-ATPase and four isoforms of the Na+/H+ exchanger (NHE-1, NHE-2, NHE-3 and NHE-4) were measured by quantitative Northern analysis in rat renal cortex and medulla following ischemia-reperfusion injury. Rats were subjected to 30 minutes of renal artery occlusion and then sacrificed either 12 or 24 hours after the occlusion was released. The most striking changes followed 30 minutes of occlusion and 12 hours of reperfusion and involved the mRNA for NHE-3 (involved in HCO3- reabsorption in proximal tubule and thick limb) and colonic H+-K+-ATPase (involved in HCO3- reabsorption in collecting duct). These changes were: (1) a approximately 75% decrease in NHE-3 mRNA in both cortex and medulla; and (2) an approximately 8-fold increase in colonic H+-K+-ATPase mRNA in the cortex. At 12 hours of reperfusion, there was a 66% reduction in the Na+/H+ exchanger (NHE-3) activity as assayed by acid-stimulated 22Na+ influx into brush border membrane vesicles (P < 0.01). After 24 hours of reperfusion, NHE-3 mRNA remained suppressed while cortical colonic H+-K+-ATPase mRNA declined to only twice the control level. Medullary colonic H+-K+-ATPase mRNA did not change significantly. Gastric H+-K+-ATPase mRNA in cortex or medulla remained the same at 0, 12, and 24 hours after reperfusion. Cortical NHE-1 increased mildly at 12 and 24 hours of reperfusion whereas a moderate decrease in NHE-2 and NHE-4 mRNAs was observed in cortex and medulla after both 12 and 24 hours of reperfusion. We suggest that overexpression of colonic H+-K+-ATPase in the early phase of renal reperfusion injury may be responsible for compensatory reabsorption of increased HCO3- load resulting from suppression of NHE-3. This was supported by a fourfold increase in colonic H+-K+-ATPase mRNA in rats treated with acetazolamide, which causes renal HCO3-wasting. Rapid decline in colonic H+-K+-ATPase expression at 24 hours after reperfusion is likely due to reduced HCO3- delivery to distal tubules resulting from decreased GFR. Overexpression of H+-K+-ATPase may be vital to acid-base homeostasis in the early phase of acute ischemic renal failure.
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PMID:Ischemic-reperfusion injury in the kidney: overexpression of colonic H+-K+-ATPase and suppression of NHE-3. 908 76

Acute uremia (ARF) causes metabolic defects in glucose and protein metabolism that contribute to muscle wasting. To examine whether there are also defects in the metabolism of essential amino acids in ARF, we measured the activity of the rate-limiting enzyme for branched-chain amino acid catabolism, branched-chain ketoacid dehydrogenase (BCKAD), in rat muscles. Because chronic acidosis activates muscle BCKAD, we also evaluated the influence of acidosis by studying ARF rats given either NaCl (ARF-NaCl) or NaHCO3 (ARF-HCO3) to prevent acidosis, and sham-operated, control rats given NaHCO3. ARF-NaCl rats became progressively acidemic (serum [HCO3] = 21.3 +/- 0.7 mM within 18 h and 14.7 +/- 0.8 mM after 44 h; mean +/- SEM), but this was corrected with NaHCO3. Plasma valine was low in ARF-NaCl and ARF-HCO3 rats. Plasma isoleucine, but not leucine, was low in ARF-NaCl rats, and isoleucine tended to be lower in ARF-HCO3 rats. Basal BCKAD activity (a measure of active BCKAD in muscle) was increased more than 17-fold (P < 0.01) in ARF-NaCl rat muscles, and this response was partially suppressed by NaHCO3. Maximal BCKAD activity (an estimate of BCKAD content), subunit mRNA levels, and BCKAD protein content were not different in ARF and control rat muscles. Thus, ARF increases branched-chain amino acid catabolism by activating BCKAD by a mechanism that includes acidosis. Moreover, in a muscle-wasting condition such as ARF, there is a coordinated increase in protein and essential amino acid catabolism.
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PMID:Mechanisms contributing to muscle-wasting in acute uremia: activation of amino acid catabolism. 951 6

We have shown previously that chronic hyperchloremic metabolic acidosis (CMA) induces severe negative nitrogen balance and renal phosphate depletion and decreases serum insulin-like growth factor-1 (IGF-1) in association with growth hormone (GH) insensitivity in humans. The present study investigated whether acidosis-induced renal nitrogen wasting and renal phosphate depletion are mediated by GH insensitivity/low IGF-1 and thereby responsive to GH treatment. The effects of GH on acidosis-induced changes in divalent cation metabolism and acidosis-induced hypothyroidism were also investigated. CMA (delta[HCO3], -10.5 mmol/L) was induced in six healthy male subjects ingesting 4.2 mmol NH4Cl/kg body weight [BW]/d for 7 days. Recombinant human GH (0.1 U/kg BW/12 h subcutaneously) was administered for 7 days while acid feeding was continued. GH increased serum IGF-1 from 22.1 +/- 1.4 to 87 +/- 8.4 nmol/L (control level, 36.4 +/- 2.2). GH decreased urinary nitrogen excretion, resulting in a cumulative nitrogen retention of 2,404 mmol, thereby correcting the acidosis-induced cumulative increase in nitrogen excretion (2,506 mmol) despite continued acid feeding. GH attenuated the acidosis-induced hyperphosphaturia (cumulative phosphate retention, 91 mmol) and corrected the hypophosphatemia. GH did not affect acidosis-induced ionized hypercalcemia, but further exacerbated acidosis-induced hypercalciuria (cumulative loss, 27.3 mmol). GH significantly further increased serum 1,25-dihydroxyvitamin D (1,25(OH)2D) and further decreased intact PTH (from 10 +/- 1 to 6 +/- 1 pg/mL). Acidosis also induced hypomagnesemia and hypermagnesuria (cumulative loss, 9.4 mmol, ie, renal magnesium wasting), a novel finding, which was significantly attenuated by GH (cumulative retention, 5.0 mmol). In conclusion, GH corrected acidosis-induced renal nitrogen wasting, which may be caused, at least in part, by decreased IGF-1 levels. GH further increased serum 1,25(OH)2D and the systemic calcium load, which account for the suppression of parathyroid hormone (PTH) despite renal PO4 retention and correction of hypophosphatemia. GH attenuated acidosis-induced renal magnesium wasting.
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PMID:Growth hormone corrects acidosis-induced renal nitrogen wasting and renal phosphate depletion and attenuates renal magnesium wasting in humans. 1038 Nov 52

Chronic metabolic acidosis (CMA) in human beings is characterized by increased renin-angiotensin-aldosterone (RAA) activity and cortisol secretion as well as nitrogen wasting. The purpose of this study was to examine whether and to what extent increased RAA activity (i.e., angiotensin II or aldosterone) regulates acid-base equilibrium in CMA and thus might co-determine the severity of acidosis. CMA was induced in 8 normal subjects by oral NH4Cl administration (2.1 mmol/kg body weight per day) for 7 days, followed by a 7-day period of spironolactone (100 mg, 4 times a day by mouth), followed by a 4-day period of spironolactone and losartan (100 mg, every day by mouth). NH4Cl feeding was continued during all study periods. Spironolactone resulted in exacerbation of acidosis ((HCO3)p decreased from 19.8+/-0.4 mmol/L to 17.7+/-0.6 mmol/L, P<.005) because of a large increase in endogenous acid production, as evidenced by significant increases in net acid excretion (116 to 185 mmol/day, P<.005), urinary anion gap (+31 mEq/day, P<.05), and sulfate excretion (+32 mEq/day, P<.05). Plasma potassium increased from 4.2 to 4.6 mmol/L (P<.05) because of decreased urinary potassium excretion (from 108 to 92 mmol/day, P<.05). Plasma angiotensin II, cortisol, aldosterone, urinary aldosterone, urinary tetrahydrocortisol, free cortisol, and nitrogen excretion increased significantly. The subsequent addition of losartan to spironolactone administration resulted in further exacerbation of acidosis ((HCO3)p decreased to 15.7+/-0.4 mmol/L, P<.05) and hyperkalemia (5.0 mmol/L, P<.05) with no change in plasma anion gap. Renal potassium excretion decreased from 92 to 73 mmol/day (P<.05) on day 1. Exacerbation of acidosis was accounted for by a renal mechanism, as evidenced by the significant decrease in net acid excretion and unchanged urinary unmeasured anion and nitrogen excretion. We conclude the following: (1) AT-1 blockade by losartan exacerbates acidosis by inducing a distal-tubular acidification defect. Angiotensin II is an important modulator of the renal acid excretory response to CMA in human beings. (2) Inhibition of aldosterone action by spironolactone in CMA results in an increase in endogenous acid production and exacerbates acidosis by a non-renal mechanism that is mediated, at least in part, by exacerbated hyperglucocorticoidism.
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PMID:Acid-base and endocrine effects of aldosterone and angiotensin II inhibition in metabolic acidosis in human patients. 1107 65

Although modest hypokalemia is frequently observed in asthmatic patients being treated with bronchodilators, profound hypokalemia and metabolic alkalosis are rarely reported in patients receiving high-dose hydrocortisone (HC). We describe a 66-year-old man who complained of generalized muscle weakness, shallow respiration, and palpitations after receiving high-dose intravenous HC (total dose, 2400 mg over 4 days) to treat a severe asthma attack. During this therapy, there was a weight gain of 1.0 kg. An electrocardiogram revealed ventricular arrhythmia with frequent premature ventricular contractions. Hypokalemia was profound, with plasma potassium (K+) concentration of 1.7 mEq/L, and associated with renal potassium wasting, as evidenced by a transtubular potassium concentration gradient of 12; metabolic alkalosis (plasma HCO3-, 37 mEq/L) was also present. When treated with spironolactone, KCl supplementation, and substitution of HC with prednisolone, his plasma K+ concentration rapidly normalized, metabolic alkalosis was corrected, and arrhythmia disappeared within 3 days. Because of unwanted mineralocorticoid side-effects, high-dose HC may cause life-threatening hypokalemia in asthmatic patients. Because of these potential risks, plasma acid-base and electrolyte concentrations should be monitored frequently in any patient treated with high-dose HC.
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PMID:Life-threatening hypokalemia in an asthmatic patient treated with high-dose hydrocortisone. 1509 Jul 54

Hypokalemic paralysis is a medical emergency due to the risks of cardiac arrhythmia, respiratory failure, and rhabdomyolysis. Besides supplementing patients with KCl to hasten recovery, the astute physician must search for the underlying cause to avoid missing a treatable and curable disorder. We report on an elderly Korean man who presented with marked limb paralysis, myalgias, and mild hypertension. He had prostate cancer treated with orchiectomy and hormone therapy 2 years previously. The major biochemical abnormalities were hypokalemia (K+: 1.7 mmol/l) associated with high renal K+ wasting and metabolic alkalosis (HCO3-: 42.6 mmol/l). Low plasma renin activity, low aldosterone concentration, and normal cortisol concentration pointed to a state of pseudohyperaldosteronism. While reviewing his drug history, the patient revealed he had been consuming eight packs (100 ml/pack) of a Korean herbal tonic daily to treat his prostate cancer for the past 2 months. A significant amount of glycyrrhizic acid (0.23 mg/ml), an active ingredient of licorice, was detected in the tonic. Discontinuation of the herbal tonic along with KCl supplementation achieved recovery in 2 weeks. As many complementary/alternative medicines for cancer contain licorice, this must be kept in mind as a cause of hypokalemia in cancer patients.
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PMID:A hidden cause of hypokalemic paralysis in a patient with prostate cancer. 1535 80

Hypophosphatemia is an X-linked dominant disorder resulting from a mutation in the PHEX gene. While osteoblast-specific expression of the PHEX transgene has been reported to decrease the phosphate wasting associated with the disease in male hypophosphatemic (HYP) mice, there are reports that the mineralization defect is only partially corrected in young animals. To test the hypothesis that osteoblast-specific expression of the PHEX gene for a longer time would correct the mineralization defect, this study examined the bones of 9-month-old male and female HYP mice and their wild-type controls with or without expression of the transgene under a collagen type I promoter. Serum phosphate levels, alkaline phosphatase activity, and FGF23 levels were also measured. Mineral analyses based on wide-angle X-ray diffraction, Fourier transform-infrared (FT-IR) spectroscopy, and FT-IR imaging confirmed the decreased mineral content and increased mineral crystal size in male HYP humerii compared to wild-type males and females with or without the transgene and in female HYP mice with or without the transgene. There was a significant increase in mineral content and a decrease in crystallinity in the HYP males' bones with the transgene, compared to those without. Of interest, expression of the transgene in wild-type animals significantly increased the mineral content in both males and females without having a detectable effect on crystallinity or carbonate content. In contrast to the bones, based on micro-computed tomography and FT-IR imaging, at 9 months there were no significant differences between the HYP and the WT teeth, precluding analysis of the effect of the transgene.
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PMID:The PHEX transgene corrects mineralization defects in 9-month-old hypophosphatemic mice. 1908 53


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