Catechol- o-methyl-transferase activity in dibutyryl cyclic AMP, prostaglandin and X-ray -induced differentiated neuroblastoma cell culture

Abstract

Catechol- o-methyl-transferase (COMT) activity was present in mouse neuroblastoma cells in culture. X-irradiation which caused morphological differentiation increased COMT activity in the neuroblastoma cells by about three-fold. The increase in enzyme activity was first observed 2 days after irradiation; however, the maximal increase occurred 3 days after X-ray exposure. The increase in enzyme activity in the irradiated cells was blocked by cycloheximide and actinomycin D. N 6O 2′ dibutyryl adenosine 3′, 5′ cyclic monophosphate (dibutyryl cyclic AMP) and prostaglandin E1 which caused morphological differentiation did not increase COMT activity during the period of observation. 3′, 5′ cyclic AMP which inhibited cell division without causing morphological differentiation had no effect on the enzyme activity, but sodium butyrate which blocked cell division without causing morphological differentiation did increase COMT activity. Data suggest that the regulation of COMT level may not be strictly linked either with the growth rate or the morphological differentiation.