The effect of intravenous infusions of ATP and dibutyryl cyclic AMP (DB cyclic AMP) on adrenocorticotrophin (ACTH) and corticosteroid release was investigated in piglets.
A consistent increase of both plasma ACTH and plasma cortisol was observed in response to infusions of 600 mg ATP/h. These responses were abolished by pretreating the animals with dexamethasone. A similar pattern of response was observed with DB cyclic AMP infused intravenously. No response occurred when 100 mg DB cyclic AMP were infused in 1 h, but there was a marked plasma corticosteroid response to an infusion of 600 mg DB cyclic AMP in 1 h. Surprisingly, this response was also abolished by pretreatment with dexamethasone.