Effects of tryptamine on plasma glucagon levels in mice.
Our previous study indicated that tryptamine induces a dose-related increase in plasma glucagon levels of mice and that this effect is mediated by the peripheral serotonin2 (5-HT2) receptor. The present paper further investigated the involvement of serotonergic and catecholaminergic systems in hyperglucagonemia elicited by tryptamine. An inhibitor of 5-HT synthesis, p-chlorophenylalanine, did not affect tryptamine-induced increases in plasma glucagon levels. Tryptamine-induced hyperglucagonemia was not inhibited by adrenalectomy or by an inhibition of catecholamine synthesis by alpha-methyl-p-tyrosine. These findings indicate that tryptamine-induced hyperglucagonemia is elicited by its direct activation of 5-HT2 receptors and is not mediated by levels of endogenous 5-HT and catecholamines. The results further suggest that the peripheral 5-HT2 receptor has a possible role in the release of glucagon.
Yamada
J
J
Department of Pharmacology, Kobe Women's College of Pharmacy, Japan.
Sugimoto
Y
Y
Kimura
I
I
Watanabe
Y
Y
Horisaka
K
K
D000315:Adrenalectomy; D000818:Animals; D010134:Fenclonine / Q000494:pharmacology; D005934:Glucagon / Q000097:blood* / Q000378:metabolism; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D011985:Receptors, Serotonin / Q000502:physiology; D012016:Reference Values; D014363:Tryptamines / Q000494:pharmacology*; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D011985:Receptors, Serotonin; D014363:Tryptamines; C030820:tryptamine; D019805:alpha-Methyltyrosine; D005934:Glucagon; D014446:Tyrosine 3-Monooxygenase; D010134:Fenclonine