The topography of mercurial lymphadenopathy in brown Norway rats.

Injection of mercuric chloride caused a progressive systemic lymphadenopathy and splenomegaly in Brown Norway (BN) but not in Lewis rats, as reported by others. We studied the number, duration and route of HgCl2 treatments and the topography of the resultant lymphadenopathy, as well as its age and strain dependency. Five injections of HgCl2 increased three-fold the weight of the lymph nodes which became considerably heavier than the spleen. Weanling rats were less susceptible than adults. A regional lymphadenopathy could not be produced. However, a synergistic interaction was observed when the systemic effects of HgCl2 were added to the regional lymphadenopathy produced by injections of metal powders, such that the lymph node mass approached 2% of body weight.