Production of “Sulphation Factor” by the Perfused Liver

Abstract

LONGITUDINAL growth of the mammalian skeleton occurs at the epiphyseal plate where chondrocytes proliferate and synthesize a matrix composed of collagen and a group of sulphated polysaccharides. In spite of the well known requirement for growth hormone to sustain longitudinal skeletal growth, a direct effect of the hormone on cartilage metabolism has not been demonstrated. The incorporation of sulphate into the organic matrix of cartilage is stimulated by a component of normal serum which is not growth hormone. This factor is absent in the serum of hypophysectomized animals, including man, but is restored by the administration of growth hormone. In addition to the stimulation of sulphate incorporation into polysaccharide, collagen synthesis and cell replication are also enhanced. Because the original assay for this component involved measurement of the incorporation of radioactive sulphate into the cartilage of hypophysectomized rats, the term “sulphation factor” was proposed by Salmon and Daughaday¹. The source of this factor as well as its composition have been unknown.