Serum leptin levels after central and systemic injection of a serotonin precursor, 5-hydroxytryptophan, in mice.
Effects of peripheral and central injections of a serotonin (5-hydroxytryptamine, 5-HT) precursor, 5-hydroxytryptophan (5-HTP), on serum leptin levels were studied in mice. Intracerebroventricular (i.c.v.) injection of 5-HTP or 5-HT did not increase serum leptin levels, although the peripheral injection of 5-HTP elicited an apparent hyperleptinemia. The elevation of serum leptin levels in mice induced by the peripheral injection of 5-HTP was inhibited by pretreatment with the peripheral aromatic amino acid decarboxylase inhibitor, benserazide. Furthermore, the peripheral injection of 5-HT increased serum leptin levels. These results suggest that the hyperleptinemia following systemic injection of 5-HTP is elicited by 5-HT formed in the peripheral system.
Yamada
J
J
Department of Pharmacology, Kobe Pharmaceutical University, Motoyamakita-machi, Higashinada-ku, 658-8558, Kobe, Japan. j-yamada@kobepharma-u.ac.jp
Ujikawa
M
M
Sugimoto
Y
Y
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D001545:Benserazide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D020738:Leptin / Q000097:blood*; D008297:Male; D051379:Mice; D012701:Serotonin / Q000494:pharmacology; D018490:Serotonin Agents / Q000494:pharmacology; D013997:Time Factors
D020738:Leptin; D018490:Serotonin Agents; D012701:Serotonin; D001545:Benserazide; D006916:5-Hydroxytryptophan