The effect of seasonal variation on benzene potentiation of rabbit kidney histidine decarboxylase.

Samples of rabbit kidney histidine decarboxylase were incubated with substrate, L-histidine, either in the presence or absence of one drop of benzene. The extent of histamine formation was then assessed in vitro on the isolated ileum of the guinea-pig. Benzene potentiated the activity of histidine decarboxylase by a factor of approximately five. This activating effect occurred only during the summer months. No potentiation of histidine decarboxylase was recorded during the winter in either control rabbits or in animals receiving ascorbic acid in their drinking water. It was concluded that this vitamin is probably not involved in the mediation of the benzene effect.