[Effect of monoamines on ACTH secretion by dispersed perfused cells from the adenohypophysis of barcino chico duck (Anas flavirostris)].
We have pursued with the characterization of ACTH secretagogues from the avian corticomelanotrophic (CM) cell, by testing the ACTH-releasing activity of various monoamines and related drugs, using an in vitro system which uses dispersed perfused duck pituitary cells. The substances used were: noradrenaline (NA), adrenaline (A), dopamine (DA), serotonin (5-HT), phenylephrine (Phe), and isoproterenol (IP). The responses obtained with the substances assayed were compared with those obtained with dilutions of duck median eminence extracts (DME). The order of "intrinsic activities" was: NA = A greater than Phe greater than IP greater than DA = 5-HT. The substances were tested within the range 10(-9)-10(-4) M. All substances tested behaved as partial agonists with respect to DME. The "intrinsic activity" (Vmax) of the most potent agonists tested, A and NA, was 0.66 of that obtained with DME. It is concluded that in the duck, the CM cells secrete ACTH in response to A and NA (and other pharmacological substances) at doses which are compatible with a physiological role of those catecholamines acting directly upon the CM cell of the avian adenohypophysis. 5-HT and DA behaved as very weak agonists in stimulating ACTH release from duck CM cells in the system employed.
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D004298:Dopamine / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004372:Ducks; D004837:Epinephrine / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D008473:Median Eminence; D018377:Neurotransmitter Agents / Q000502:physiology*; D009638:Norepinephrine / Q000502:physiology; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D012701:Serotonin / Q000502:physiology; D014020:Tissue Extracts / Q000494:pharmacology*
D018377:Neurotransmitter Agents; D014020:Tissue Extracts; D012701:Serotonin; D000324:Adrenocorticotropic Hormone; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine
Effecto de monoaminas sobre la secreción de ACTH en células dispersas, perfundidas, de la adenohipofisis del pato barcino chico (Anas flavirostris).