Effect of a New Steroid on Phospholipid Metabolism of the Chick

¹ From the Division of Biological Research, G. D. Searle and Company, Chicago, Illinois

The incorporation of P³² into the phospholipid of plasma, liver, kidney and aorta of chicks treated with a synthetic steroid, methoxy-methyl-estratriene-diol (SC-6924), was measured. In the absence of the liver there was virtually no new plasma phospholipid formed and neither kidney nor aorta phospholipid synthesis was affected by the steroid treatment. Administration of SC-6924 enhanced incorporation of the isotope into the phospholipids of liver and plasma of treated birds. Specific activity-time curves confirmed the hypothesis that liver phospholipid is the precursor of plasma phospholipid. It was apparent that the induced modification of lipid metabolism involved not only hepatic synthetic mechanisms but also catabolic systems concerned with phospholopid metabolism.