Biochemistry & Pharmacology: Open Access
Open Access

Abstract

Relationship between Partition Coefficients of Carboxylic Acids and Changes in Osmotic Resistance in Rat Erythrocytes In vitro

Hitoshi Mineo

We examined monocarboxylic and dicarboxylic acids and their partition coefficients for osmotic fragility (OF) in isolated red blood cells (RBCs) in rats. The dense packed RBC was incubated in a phosphate–NaCl buffer solution containing each carboxylic acid at 0 to 100 mM at 37ºC for 1 h. The RBC suspensions were transferred into the OF test tubes containing NaCl from 0.2 to 0.9%. The hemoglobin concentration was determined and NaCl concentration inducing 50% hemolysis was calculated as OF value. The OF in RBCs was dose-dependently increased by exposure to some of monocarboxylic acids possessing certain length of hydrocarbons with more than 4 carbons. A positive and statistically significant correlation was obtained between the partition coefficients and the degree of change in OF for monocarboxylic acids. Dicarboxylic acids corresponded with the monocarboxylic acids had either no effect or rather decreased OF, and there was no correlation between the partition coefficients and change in OF for these acids. The partition coefficients of the monocarboxylic acids were higher than those for the corresponding dicarboxylic acids. Whereas monocarboxylic acids are thought to act on the hydrophobic acyl-chain of phospholipids, which exists in a deeper region, dicarboxylic acids act on the interface region, which is hydrophilic and in a shallower area of the RBC membrane. Both carboxylic acids are speculated to cause physicochemical changes in the deep or swallow portion of phospholipid layer through different mechanisms and result in changes in the resistance to osmotic pressure in the rat RBC membrane.