Interaction of Progesterone and Aldosterone with Red Blood Cells of the Rat

摘要

The interaction of progesterone and aldosterone with red blood cells was studied in an in vitro system by equilibrium dialysis technique. The uptake of progesterone by the erythrocytes is of the order of 70-85 percent of the total steroid in contact with the red blood cell, whereas the uptake of aldosterone is insignificant. Consideration of molar ratios of hemoglobin and steroid and calculations of binding affinity of steroid to hemoglobin suggest that the steroid does not enter into the red blood cells, but could be absorbed at the cells' surface. Studies on the metabolism of progesterone and aldosterone by the red blood cells in vitro show that no metabolites of the two steroids occur. (Author)