Reticuloendothelial cell-steroid hormone relationships

The reticuloendothelial system, first named by Aschoff in 1913, is a system of cells distributed throughout the tissues and organs of the body. This system of cells serves as a source of rapidly mobilized macro-phages and also participates in the storage of materials and the support of reticular type tissues. Other functions of the reticuloendothelial system in the mature organism are the production of all types of blood cells, the production of antibodies, and the storage of various substances. Because of the varied potentialities of this system of cells, its activity is of great importance to the maintenance of homeostasis. Early investigators proposed that the reticuloendothelial system actually comprised a syncitium of cells distributed throughout the body. This hypothesis is open to considerable question. However, the ability of the cells of this system to be rapidly activated and its multipotential ability in both normal and pathologic states is beyond question. Surprisingly, no attempts have been made to study steroid biotransformation by isolated reticuloendothelial cells. However, numerous studies of steroid hormone effects on reticuloendothelial system functions are in the literature. The studies to be reported here correlate the participation of the reticuloendothelial cell in the biotransformation and biosynthesis of steroid hormones. Isolated reticuloendothelial cells an4 whole cell preparations from tissues where reticuloendothelial cells were stimulated were used. The participation of reticuloendothelial cells in two phases of steroid physiology have been studied: 1) the biotransformation of progesterone~4-Cl4 to adrenocortical steroids, and 2) the conjugation of various radioactively labelled steroid hormones to water-soluble compounds.