SHORT COMMUNICATION Induction of ornithine and histidine decarboxylases in hamster tongue after application of the tumor promoter 7, 12-dimethy1-1, 2-benzanthracene (DMBA)

It has been reported that ornithine decarboxylase (ODC) and histidine decarboxylase (HDC) levels are high in malignant growing tissues and it is suggested that diamines (putrescine and histamine) may play an important role in the tumor development process1). Schayer2) and Kahlson and Rosengren3) suggested that the rapid increase in HDC activity (e.g. in tumors) was associated with " inducible HDC " in non-mast cells and that histamine synthesized by inducible HDC was not stored in tissues. A single application of a tumor promoter (e.g. Phorbol ester) to the mice skin increased the activities of HDC and ODC in the skin4,5,). Taguchi et al.5) reported that the induction of HDC in the skin after a single application of phorbol ester took place in non-mast cells. On the other hand, Bianchi et al.6) demonstrated that a remarkable accumulation of mast cells was observed in the skin of hamsters pained with 7, 12-dimethyl-1, 2-benzanthracene (DMBA). Repeated painting of DMBA to the hamster tongue is known to cause an experimental tumor of the tongue7). The tongueis one of the tissues which have many mast cells just like skin8). The presence of non-mast cells containing histamine has not been demonstrated in the tongue yet. The present experiments were carried out to see the possibility of the induction of " inducible HDC " in non-mast cells in the tongue. Materials and Methods