Isolation, amino acid sequence and action of guinea-pig ACTH on aldosterone production by glomerulosa cells

Though minor sequence differences between-species have been reported for adrenocorticotrophin, ACTH(1-39), the steroidogenic moiety ACTH(1-24) has appeared invariant in mammals. We here report the isolation, purification and amino acid sequencing of guinea-pig (GP) ACTH in which Pro²⁴ is replaced by Ala²⁴, and the demonstration that GP-ACTH stimulates aldosterone production to maximal levels well above those seen with human ACTH(1-39) or Synacthen, ACTH(1-24) amide, the synthetic ACTH fragment widely used for diagnostic and therapeutic purposes.