Suppression of 2', 3'-cyclic nucleotide 3'-phosphohydrolase activity in suckling rat brain by ACTH

Administration of ACTH at two different doses (0.05 and 0.5 microgram/g/day) to suckling rats resulted in the suppression of both the body and brain weight gains and the developmental increase in brain CNPase activity, and the suppression of the brain CNPase activity persisted for 3 weeks (up to the end of the experiment) after the cessation of ACTH administration in the suckling period, while the suppression of the body and brain weight gains was noticed only during the administration period. The authors emphasized the possibility that long-term therapy with massive doses of ACTH for infantile spasms may be hazardous to the developing brain in many ways.