Percutaneous absorption and metabolism of dinitrochlorobenzene in vitro

Abstract.

Dinitrochlorobenzene (DNCB) absorption through mouse and rat dorsal skin, pig ear skin and human abdominal skin in vitro was determined, and local metabolism to the glutathione conjugate was related to glutathione transferase activities and glutathione status in the skin. Absorption studies were conducted using skin mounted in a flow-through diffusion cell with tissue culture medium as receptor fluid. DNCB applied to the surface of skin in acetone penetrated through 26-day-old rat skin better than through the skin of the other species investigated. The amounts of absorption through pig and human skin and conjugation formation were similar. In general, occlusion resulted in increased penetration of DNCB but no change in conjugation. Human skin showed the highest glutathione-S-transferase activity towards DNCB, followed by 26-day-old rat, pig, mouse and neonatal rat skin. Levels of glutathione were highest in mouse skin, followed by neonatal rat, 26-day-old rat, pig and human skin, with pig and human skin showing similar levels. These studies indicated that the glutathione level in skin was the determining factor influencing the degree of DNCB conjugation during percutaneous absorption, and this was greatly depleted during percutaneous penetration of DNCB.