MCH-induced pigment aggregation in teleost melanophores is associated with a cAMP reduction.
It has previously been shown that alpha 2-adrenoceptors are involved in noradrenaline-induced pigment aggregation within fish melanophores. In the present investigation, melanin concentrating hormone (MCH) elicited pigment aggregation (EC50 approximately 1 x 10(-7) M) that was associated with a significant reduction in the cAMP content; 1 x 10(-7) M MCH reduced the cAMP content from a basal level of 50.4 +/- 2.8 pmol/mg protein to 36.9 +/- 3.8 pmol/mg protein. Like the alpha 2-adrenoceptor-induced pigment aggregation, the MCH response was effectively blocked by the adenylate cyclase stimulator forskolin. These findings suggest that attenuation of cAMP may serve as an intracellular signal transduction mechanism for both MCH and noradrenaline.
Svensson
S P
SP
Department of Pharmacology, University of Linköping, Sweden.
Norberg
T
T
Andersson
R G
RG
Grundström
N
N
Karlsson
J O
JO
D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D005399:Fishes; D007028:Hypothalamic Hormones; D007424:Intracellular Fluid / Q000378:metabolism; D008543:Melanins / Q000494:pharmacology*; D008547:Melanophores / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010860:Pigments, Biological / Q000378:metabolism*; D010907:Pituitary Hormones / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D015016:Yohimbine / Q000494:pharmacology
D007028:Hypothalamic Hormones; D008543:Melanins; D010860:Pigments, Biological; D010907:Pituitary Hormones; D005576:Colforsin; D015016:Yohimbine; C019463:melanin-concentrating hormone; D000242:Cyclic AMP