Preface--series of papers relating reproductive activity to selected organosiloxane chemicals

6 papers investigating the biological activity of experimental and commercially available cyclic and linear organosiloxane polymeric fluids and chemically related nonpolymeric pure chemicals are summarized. Toxicity studies of an equilibriated copolymer of mixed cyclosiloxanes ((PhMeSiO)x(Me2SiO)) referred to as PMxMMy have shown gross testicular atrophy and microscopic alteration of spermatogenesis in rabbits when the compound is administered percutaneously. Administration by the po route had similar effects in the rat and monkey. Doses of PMxMMy sufficiently high to produce toxic effects in the maternal system of rabbits affected fetal resorption and pup survival. Dermal application of PMxMMy did not markedly increase blood and urine silicone levels in humans. In rats PMxMMy interrupted the normal estrus cycle prevented implantation affected the development of the external genitourinary structure of female pups and interfered with the later stages of spermatogenesis during treatment. Organosiloxane fluids used in industry and as components in cosmetics did not have the adverse effects of PMxMMy. Compounds related to the polymeric mixture depressed male reproductive function in the mouse rat and rabbit the most active compound being 2 6-cis-diphenylhexamethylcyclotetrasiloxane .