INHIBITION OF THE SECRETION OF INTERMEDINE BY D-LYSERGIC ACID DIETHYLAMIDE (LSD 25) IN THE TOAD, XENOPUS LAEVIS

Abstract

LSD-25 causes a significant pigment concentration in the melanophores of Xenopus laevis. The extent and duration of the pigment concentration reaction in the melanophores following LSD-25 administration is directly proportional to the concentration of the drug administered. Intermedine causes pigment dispersion in the melanophores of Xenopus which are adapted to a white background and in melanophores in which melanin-concentration has been induced by the administration of LSD-25. The pigment dispersing reaction caused by corticotropin (intermedine) in the melanophores of isolated Xenopus-webs is not influenced by LSD-25 in different concentrations. It is suggested that in this species, LSD-25 does not act directly on the melanophores but that the drug inhibits the production and/or the secretion of the melanophore hormone in the intermediate lobe of the pituitary.