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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in carbonic anhydrase (CA) activity have been associated with metabolic diseases like diabetes mellitus and hypertension. To explore the exchange of H+ for Na+ and 22Na+, the sodium pool, CA activity and H2O content in erythrocytes from the two groups of diabetic chronic renal failure (CRF) patients with and without hypertension before dialysis were studied. The results were compared with those from the normotensive controls. The CA activity was determined spectrophotometrically, the sodium pool by ouabain insensitive 22Na+ influx and the percent H2O content gravimetrically. The 22Na+ influx in CRF patients with hypertension was significantly higher (p less than 0.025) than in the normotensive CRF patients and the controls. The levels of CA activity (U/min/mL) and the percent H2O content were significantly different in the hypertensive and the normotensive CRF patients from the control group (2.24 +/- 0.69 and 67.11 +/- 1.33, 1.95 +/- 0.63 and 66.43 +/- 1.51, 1.44 +/- 0.07 and 63.61 +/- 1.72, respectively). The present study implies a relationship between the 22Na+ influx and CA activity in CRF patients with hypertension. The variation of CA activity may thus result in changes in H+ production and ultimately in the intracellular Na+ pool.
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PMID:Erythrocyte carbonic anhydrase: a major intracellular enzyme to regulate cellular sodium metabolism in chronic renal failure patients with diabetes and hypertension. 161 Mar 83

1. A sustained high glomerular filtration rate in diabetes mellitus is associated with increased proximal reabsorption, suggesting alterations in the tubuloglomerular feedback system. To test this hypothesis, renal function was studied in eight control subjects and 14 recent-onset euglycaemic insulin-dependent diabetic patients before and after infusion of the carbonic anhydrase inhibitor, acetazolamide (5 mg/kg body weight). 2. Acetazolamide induced a dramatic fall in glomerular filtration rate in both diabetic patients and control subjects (from 138 +/- 5 to 114 +/- 4 and from 127 +/- 3 to 113 +/- 2 ml min-1 1.73 m-2, respectively, P less than 0.0001). This fall in glomerular filtration rate was strongly correlated with the acetazolamide-induced decrease in absolute proximal reabsorption calculated by using lithium clearance. 3. To further assess the potential role of angiotensin II in the acetazolamide-induced tubulo-glomerular feedback response, 11 additional diabetic patients were investigated before and after the administration of acetazolamide plus the angiotensin-converting enzyme inhibitor, enalaprilat (1.25 mg intravenously). Despite the effective blockade of angiotensin II formation and a slight decrease in renal vascular resistance, the glomerular filtration rate fell significantly and by a similar magnitude as seen with acetazolamide alone. 4. These results indirectly suggest that there is an altered basal tubulo-glomerular feedback system in diabetic patients but a normal response to the increase in distal delivery. No convincing role for an angiotensin II-mediated effect on the afferent limb of the tubuloglomerular feedback response could be demonstrated.
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PMID:Feedback-mediated reduction in glomerular filtration during acetazolamide infusion in insulin-dependent diabetic patients. 165 91

Most work with the male rat liver carbonic anhydrase isozymes in the past decade has centered on the cytosolic CA III and the mitochondrial CA V. This paper reports that the relative activity of both isozymes is altered in streptozotocin-diabetes. Carbonic anhydrase activity of perfused liver homogenates and disrupted, isolated mitochondria was measured by the mass spectrometric 18O decay technique at 37 degrees C. The contributions of the different isozymes were determined based on intracellular location and sensitivity to acetazolamide inhibition. Diabetes resulted in a twofold increase in the activity of CA V but a halving in the activity of CA III. This is the first time that liver CA V has been shown to be altered by physiological stress. The total carbonic anhydrase activity in the diabetic rat liver was unaltered compared with control rats; however, CA III never accounted for more than 50% of this activity. Since CA isozymes I, II, and IV together account for 30% of the CA activity in control rats and 70% in diabetic rats it is concluded that one or more of these isozymes is subject to regulation in the diabetic male rat. The increase in CA V during diabetes is in accord with this isozyme having an important function in provision of substrate for hepatic gluconeogenesis and ureagenesis.
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PMID:Differential regulation of hepatic carbonic anhydrase isozymes in the streptozotocin-diabetic rat. 210 33

One of the four discrete isoenzymes of carbonic anhydrase hitherto characterized, CA III, has the lowest turnover rate and the greatest resistance to inhibition by sulphonamides. Streptozotocin-induced diabetes mellitus resulted in a reduction in acetazolamide-resistant activity of carbonic anhydrase in the liver, but not in tonic skeletal muscle, of adult male rats. The hepatic activity declined with apparent first-order kinetics [calculated rate constant (k) 0.089 day-1] to a minimum of approx. 6% of control values; the reduction in activity was moderated by administration of insulin.
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PMID:Acetazolamide-insensitive carbonic anhydrase activities in liver and tonic skeletal muscle of adult male rats with streptozotocin-induced diabetes mellitus. 212 9

This paper reports CABG which was successfully performed on a male patient of 70-year-old with severe chronic obstructive pulmonary disease (FEV1.0% 43%) and diabetes mellitus. The patient necessitated reintubation because of hypercapnea on 18 POD in spite of bronchodilator and physical therapies. Long respiratory care was continued after tracheotomy, and finally he could wean from the mechanical respiratory care utilizing acetazolamide (carbonic anhydrase inhibitor) on 59 POD.
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PMID:[An aged case of coronary-aorta bypass grafting surgery (CABG) with severe chronic obstructive pulmonary disease]. 225 Apr 45

Glycosylated form of carbonic anhydrase isozyme I was found in human erythrocytes. The percent of glycosylated enzyme of the total erythrocyte carbonic anhydrase I of patients with diabetes mellitus was significantly higher than that from normal controls. Characterization of the glycosylated carbonic anhydrase I was studied using an enzyme purified from diabetic patients. The glycosylated enzyme showed a slightly acidic isoelectric point in comparison with that of a nonglycosylated enzyme. The specific activity of the glycosylated enzyme was approximately 40% of that of the normal enzyme, and the immunological activity decreased to 52% of that of the normal enzyme. Estimation of carbohydrates which may form a ketoamine linkage with the enzyme was studied using [3H]-labelled glycosylated enzyme synthesized by incubation of the enzyme with [3H]-D-glucose in vitro, and it was found that one mol of glucose binds to one mol of enzyme. Exposure of red cells to a higher concentration of glucose in diabetics brought about glycosylation of carbonic anhydrase, which is associated with its low activity enzymatically and immunologically.
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PMID:Estimation and characterization of glycosylated carbonic anhydrase I in erythrocytes from patients with diabetes mellitus. 311 73

Insulin has a plethora of metabolic effects but its action on carbonic anhydrase-III (CA-III), a key enzyme in acid-base regulation, has been little studied. The present studies examined the effects of streptozotocin induced diabetes on the concentrations of CA-III. The concentration of CA-III in the liver, muscles and serum of rats with experimental diabetes mellitus was measured by the method of enzyme-immunoassay. Streptozotocin-induced diabetes mellitus resulted in a reduction in concentration of CA-III in the liver and serum, but not in skeletal muscles, of adult male rats. A 98% reduction in hepatic CA-III content relative to control values was observed. The reduction in CA-III content in the liver was restored to control value by administration of insulin. The CA-III content in serum of diabetic rats declined to approx. 25% of control values, but the reduction was unaffected by administration of insulin. The concentration of CA-III in the liver and serum of diabetic rats was not influenced by administration of methyltestosterone. Although the content of CA-III in m. rectus femoris, m. tibialis craniaris and m. soleus differed, no significant difference of CA-III content was found between diabetes mellitus and control rats. The effect of chronic diabetes mellitus on CA-III content was obviously different between liver and muscle, suggesting that the regulation of CA-III biosynthesis differs between these two tissues. These results suggest that biosynthesis of CA-III in hepatocytes of rats is influenced by irregular patterns of GH secretion brought about by diabetes mellitus.
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PMID:Determination of carbonic anhydrase-III by enzyme-immunoassay in liver, muscle and serum of male rats with streptozotocin-induced diabetes mellitus. 778 58

Lithium is the best available marker of proximal tubular reabsorption of fluid. The first part of the present thesis reviews the background for the use of the lithium clearance (CLi) method. Micropuncture studies on proximal reabsorption of lithium, showed that CLi is a reasonably correct measure of end-proximal fluid delivery rate, even during osmotic diuresis. During severe salt restriction, distal reabsorption of lithium renders the CLi method inappropriate in animals, but this problem does probably not occur in humans. The major current issue is whether a quantitatively significant reabsorption of lithium occurs in the loop of Henle. Available evidence is in accord with the interpretation that it does not occur. The interpretation of results form CLi studies depends to a surprising degree on the investigators beliefs about renal physiology. In the evaluation of proximal tubular function, the relevant parameter is the absolute proximal reabsorption rate of fluid and sodium. In the evaluation of integrated distal tubular reabsorption of sodium, the relevant parameter is the fractional distal reabsorption rate of sodium. The fractional CLi does not give meaningful information, and calculated absolute distal reabsorption rate of sodium is inherently not suited to detect modest changes in distal reabsorption leading to large changes in sodium excretion. Results from the use of the CLi method in relation to diabetes are reviewed in the second section. Even in IDDM patients with early diabetic nephropathy, the proximal reabsorption rate is elevated, resulting in a normal CLi despite glomerular hyperfiltration. Overnight euglycemia did not change GFR in IDDM patients, but during maintained euglycemia, GFR was normalized. A few hours of hyperglycemia prevented the decline in GFR, whereas CLi was unchanged. Thus hyperglycemia produced changes in renal function similar to those observed previously, but the time-course of the effect of euglycemia on kidney function is delayed. Plasma levels of atrial natriuretic peptide, renin and glucagon were not importantly affected by plasma glucose. In NIDDM patients CLi was normal, despite slight hyperfiltration, although this observation must be confirmed in a study with larger sample size. Prompted by the clinical observation of a marked decline in the GFR induced by carbonic anhydrase inhibitors, we studied the renal effects of acetazolamide in a controlled study.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Lithium clearance in the evaluation of segmental renal tubular reabsorption of sodium and water in diabetes mellitus. 818 64

Acetazolamide (ACTZ), a carbonic anhydrase inhibitor, causes a fall in renal plasma flow and glomerular filtration (GFR). It is generally believed that the tubuloglomerular feedback (TGF) mechanism is responsible. This study examined whether, in patients with diabetes mellitus, the renal hemodynamic response to ACTZ is intact and whether the angiotensin-converting enzyme inhibitor, enalapril, which would be expected to block TGF, attenuates this response to ACTZ. Six men with insulin-dependent diabetes mellitus lived in a clinical research center for 8 weeks and received enalapril 5-15 mg/day from the third through sixth week. At 2, 6 and 8 weeks p-aminohippurate (PAH) and inulin clearances were performed over eleven 30-min periods. ACTZ (150 mg) was given intravenously after 180 min. In both the pre- and postenalapril studies, PAH clearance fell after ACTZ administration (-60 +/- 15 and -66 +/- 20 ml/min/l1.73 m2, respectively, p < 0.05 for each study). In contrast, with enalapril treatment PAH clearance after ACTZ tended to rise (29 +/- 12 ml/ min/1.73 m2, p = 0.07). GFR after ACTZ fell during the pre- and postenalapril studies (-19 +/- 3 and -13 +/- 1 ml/min/1.73 m2, respectively, p < 0.05 for each study) but not with enalapril treatment (-6 +/- 3 ml/min/1.73 m2). After ACTZ was administered, estimated renal vascular resistance rose during both the pre- and postenalapril studies (p < 0.05 and p < 0.01, respectively) and fell with enalapril treatment (p < 0.05). These data indicate that enalapril alters the renal hemodynamic effects of ACTZ in patients with diabetes mellitus, possibly by inhibiting tubuloglomerular feedback.
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PMID:Enalapril attenuates the renal hemodynamic effect of acetazolamide in patients with diabetes mellitus: possible implications for tubuloglomerular feedback. 873 85

Carbonic anhydrase activity was measured in lyzed erythrocytes from smoking and non-smoking young men as well as from diabetic and healthy young women. Enzyme activity was determined by a changing-pH-assay, using a stirred reaction vessel and glass pH electrode. CAA was lower in smokers than in non-smokers. Furthermore, it was lower in diabetics than in nondiabetic controls. We conclude that cigarette smoking as well as diabetes mellitus may reduce erythrocyte carbonic anhydrase activity.
Exp Clin Endocrinol Diabetes 1997
PMID:Erythrocyte carbonic anhydrase activity in smokers and in diabetic patients. 928 36


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