Acetazolamide-insensitive carbonic anhydrase activities in liver and tonic skeletal muscle of adult male rats with streptozotocin-induced diabetes mellitus

The effects of anti-epileptic drugs on human erythrocyte carbonic anhydrase I and II isozymes

Carbonic anhydrase (CA) is an enzyme which plays a role in various homeostatic mechanisms, such as acid-base balance and electrolyte secretion in a various tissues. This study was aimed at determining and comparing possible alterations in activity of this enzyme caused by the use of old (Carbamazepine, Phenytoin Sodium, Sodium Valproate) and new (Levetiracetam, Pregabalin, Gabapentin, Oxcarbazepine) anti-epileptic drugs. Blood samples were collected from the volunteers. The blood samples were centrifuged to separate plasma and erythrocyte package. Hemolysate was prepared from the red cells. CA I and II were purified from human erythrocytes by a simple one step procedure using Sepharose 4B-L-tyrosine-sulfonamide affinity column. CA I and II isozymes were treated with some anti-epileptic drugs, then the inhibition or activation of enzyme determined. The results of this study show that Levetiracetam is the most effective inhibitor for human erythrocytes carbonic anhydrase compared with the other anti-epileptic drugs.

Inter-organ proteomic analysis reveals insights into the molecular mechanisms underlying the anti-diabetic effects of cis-9, trans-11-conjugated linoleic acid in ob/ob mice

cis-9, trans-11-Conjugated linoleic acid (c9 t11 CLA) exerts anti-diabetic effects by improving systemic insulin sensitivity and inflammation. Levels of CLA in beef can be increased by feeding cattle on pasture. This study aimed to explore the efficacy of a CLA-rich diet (0.6% w/w c9 t11 CLA), presented as beef enriched with CLA or beef supplemented with synthetic CLA (c9 t11 CLA), for 28 days on molecular biomarkers of the metabolic syndrome, and adipose, hepatic, and skeletal muscle proteome in male ob/ob mice. Despite equal weight gain, CLA-fed mice had lower plasma glucose, insulin, non-esterified fatty acid, triacylglycerol and interleukin-6, and higher adiponectin concentrations than controls. c9 t11 CLA induced differential regulation of redox status across all tissues, and decreased hepatic and muscle endoplasmic reticulum stress. CLA also modulated mechanistic links between the actin cytoskeleton, insulin signalling, glucose transport and inflammation in the adipose tissue. In the liver and muscle, c9 t11 CLA improved metabolic flexibility through co-ordination between carbohydrate and energy metabolism. c9 t11 CLA may ameliorate systemic insulin sensitivity in obesity-induced diabetes by altering cellular stress and redox status, and modulating nutrient handling in key insulin-sensitive tissues through complex biochemical interplay among representative proteomic signatures.

In Vitro and in Vivo Effects of Dantrolene on Carbonic Anhydrase Enzyme Activities

The effects of dantrolene were investigated on carbonic anhydrase (CA) enzyme activities in in vitro human and in in vivo Sprague-Dawley rat erythrocytes. For in vitro study, human carbonic anhydrase-I (HCA-I) and -II (HCA-II) were purified by Sepharose 4B-L-tyrosine-sulfanylamide affinity chromatography, rats were used for in vivo study. In vivo and in vitro CA enzyme activity was determined colorimetrically using the CO(2)-hydration method of Wilbur and Anderson. Dantrolene (1.64 x 10(-5)-6.56 x 10(-5) M) showed in vitro inhibitory effects on HCA-I and HCA-II hydratase activity, when determined using the CO(2)-hydratase method. 50% inhibitory concentration (IC(50)) was 4.09 x 10(-5) M for HCA-I and 3.24 x 10(-5) M for HCA-II. Rat erythrocyte CA activity was significantly inhibited by 10 mg/kg dantrolene for up to 3 h (p<0.001) following intraperitoneal administration. In conclusion, Dantrolene inhibited the carbonic anhydrase enzyme activity under in vitro and in vivo conditions.

Effects of gentamicin sulfate on enzyme activities of carbonic anhydrase from human erythrocytes in vitro and from rat erythrocytes in vivo

The effects of gentamicin sulfate on carbonic anhydrase (CA) enzyme activity in in vitro human and in in vivo rat erythrocytes were investigated. For in vitro study, human carbonic anhydrase-I and -II (HCA-I and HCA-II) were purified by affinity-column chromatography, and rats were used for in vivo study. In vivo and in vitro CA enzyme activity was determined colorimetrically using the CO2-hydration method of Wilbur and Anderson as modified by Rickli et al. Gentamicin sulfate (1.98-9.90 mM) showed in vitro inhibitory effects on HCA-I and HCA-II hydratase activity up to a 2 mM concentration, when determined using the C02-hydratase method. Rat erythrocyte CA activity was significantly inhibited for up to 3 h (p<0.001) following intramuscular administration of gentamicin sulfate to Sprague-Dawley rats (3.2 mg/kg body weight). In conclusion, gentamicin sulfate inhibits CA enzyme activity in vivo and at low concentrations in vitro, but activated it at high concentrations (> or = 4 mM) in vitro.

Effects of some medical drugs on enzyme activities of carbonic anhydrase from human erythrocytes in vitro and from rat erythrocytes in vivo

In this study, firstly, the effects of sodium ampicillin, magnesium sulfate, and sodium dipyrone on human carbonic anhydrase (HCA) (EC 4.2.1.1.) isozymes have been investigated in vitro. Human erythrocyte CA-I and CA-II isozymes were separately purified by affinity chromatography. Inhibition or activation effects of three different medical drugs on HCA isozymes were determined using the CO(2)-Hydratase method by plotting activity %vs [medical drug]. I(50)values of the drugs exhibiting inhibition effects were found by means of these graphs. It was observed on HCA-I hydratase activity that sodium ampicillin and sodium dipyrone showed inhibition and activation effects, respectively. However, magnesium sulfate showed no effect. It was observed on HCA-II hydratase activity that sodium ampicillin and magnesium sulfate showed an inhibition effect, and sodium dipyrone showed an activation effect. In addition, in vivo studies were performed for these medical drugs in Sprague-Dawley rats. It was demonstrated that CA in erythrocytes was significantly inhibited by these drugs in 3 h.

Determination of carbonic anhydrase-III by enzyme-immunoassay in liver, muscle and serum of male rats with streptozotocin-induced diabetes mellitus

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.