Erythrocyte cation transport in obesity, hypertension, and during antihypertensive drug therapy.

The number and activity of erythrocyte ATPase-dependent sodium-potassium pump units were increased in obese subjects (p = 0.02). No link was observed between the number or activity of the pump units and hypertension. The ouabain-insensitive rubidium (i.e. potassium) transport was not associated with relative body weight or blood pressure status. Sodium-lithium countertransport correlated significantly with obesity but not with blood pressure status. In the hypertensive patients, before or after therapy with verapamil, hydrochlorothiazide, pindolol or atenolol there were no significant differences in cation transport. We propose that the correlation between obesity and essential hypertension cannot be explained by these two cation transport systems.

Unusual association of hyperkalemia and hypertension.

We report an unusual association of hyperkalemia, mild hyperchloremic acidosis, and hypertension in a young woman. Pseudohyperkalemia, Addison's disease, renal insufficiency, classical hyporeninemic hypoaldosteronism, isolated hypoaldosteronism, and iatrogenic causes were excluded. The patient's findings were compatible with a rare syndrome designated as type II pseudohypoaldosteronism, Gordon's syndrome.

Red-cell sodium-potassium pump and sodium-lithium countertransport in human obesity. Re-evaluation of the methods and association in a Finnish population.

Specific ouabain binding, active rubidium transport and sodium-lithium countertransport were studied in erythrocytes of 55 normal weight (BMI less than 27), 10 overweight (27 less than or equal to BMI less than 32) and 27 obese (BMI greater than or equal to 32) Finnish subjects after re-examination of the methods. Intra-assay variation coefficients for these three determinations were 6 percent, 6 percent and 12 percent, respectively. When samples from the same subjects were analyzed again after one month interval no significant differences were obtained between the measurements. However, storing of the cells at +4 degrees C increased Na-K-ATPase mediated rubidium transport about 1.5-fold within one day which may partly account for the discrepancies between the previously reported results. Specific ouabain binding of the overweight group appeared to be slightly lower (13.4 percent, P less than 0.05) whereas that of the obese subjects was slightly higher (8.7 percent, P less than 0.05) in comparison with normal weight subjects. Also in active rubidium transport and sodium-lithium countertransport the values of the obese subjects were significantly higher (P less than 0.01, and P less than 0.05, respectively) than those of the normal weight subjects. Furthermore, there existed a significant correlation between active rubidium transport and body mass index (r = 0.34; P less than 0.001) and also between active rubidium transport and specific ouabain binding (r = 0.67; P less than 0.001). In spite of these differences between obese and normal weight subjects there existed considerable overlapping between the groups, and these changes cannot be used as diagnostic tools in screening persons metabolically susceptible to obesity.

Affinity chromatography of B6-vitamin-dependent enzymes: purification of pig-heart branched-chain amino acid transaminase.

Pig-heart branched-chain amino acid transaminase (EC 2.6.1.42) was purified to near homogeneity with a yield of 27%. A prepurification was performed by heat treatment, gel chromatography and DEAE-Sepharose methods. For the final step, several affinity gels were tested and the one containing cycloserine coupled to CNBr-activated Sepharose 4B was selected. This effected an additional five-fold purification with a yield of 60%. The present affinity results are compared with corresponding studies with other aminotransferases in an attempt to find possible universal techniques for their purification.