Influence of melatonin and N-acetylserotonin on the cyclic AMP concentration in the rat thyroid lobes incubated in vitro.
Effects of melatonin and N-acetylserotonin on the cyclic AMP (cAMP) concentration in the organ-cultured rat thyroid gland were investigated. Exposure of the thyroid explants to melatonin (10(-8) M) resulted in a decrease of cAMP levels. Melatonin at higher concentrations (10(-7) M and/or 10(-6) M) failed to influence the thyroid cAMP level. N-acetylserotonin (10(-6) M), like melatonin in the lowest concentration employed, reduced cAMP concentrations in the thyroid explants when compared with controls. Unexpectedly, melatonin (at a concentration of 10(-7) M) added to the incubation medium with TSH (60 mU/ml), decreased the cAMP concentration in the thyroid compared with the group exposed to melatonin (10(-7) M) alone.
Lewiński
A
A
Department of Experimental Endocrinology and Hormone Diagnostics, Institute of Endocrinology, Medical Academy of Lódź, Poland.
Sewerynek
E
E
Zerek-Mełeń
G
G
Kunert-Radek
J
J
Pawlikowski
M
M
Karasek
E
E
D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D008297:Male; D008550:Melatonin / Q000502:physiology*; D009924:Organ Culture Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000031:analogs & derivatives* / Q000502:physiology; D013961:Thyroid Gland / Q000378:metabolism*; D013972:Thyrotropin / Q000502:physiology
D012701:Serotonin; D013972:Thyrotropin; D000242:Cyclic AMP; D008550:Melatonin; C006389:N-acetylserotonin