Glucocorticoid receptor number and intracellular water space

In order to elucidate the relationship between cell water content and number of glucocorticoid receptors, eleven normal and malignant lymphoid or myelomonocytic cell types originating from mouse, rat and man were investigated. The cellular water space was measured with 3H2O, and glucocorticoid receptor number was measured in a whole-cell binding assay with [3H]dexamethasone at 30 and 37 degrees C. The intracellular water phase concentration of glucocorticoid receptors (around 40 nmol/l cell water), and the dependence of receptor affinity on temperature were similar in normal and malignant rodent and human cells. It is concluded that comparisons of glucocorticoid receptor levels are best made on the basis of intracellular receptor concentrations.