MELANOPHORE REACTION AND ADRENOCORTICOTROPHIC HORMONE

Abstract

The melanophore-expanding reaction (MER) is produced by many common solvents and buffers in R. esculenta (hypophysectomized, adult) but not in X. laevis (tadpoles). The highest MER index was 3. Histamine, aqueous adrenal cortex extract, cortisone and chorionic gonadotropin did not produce MER. All pituitary extr. contained MER principle, the highest concn. being in posterior pituitary extracts. Among purified extracts, intermedin was most potent, ACTH next, and the others much less effective. The MER concns. in thyrotropin, prolactin and somatotropin are so small as to suggest contamination with this principle.