Hyperleptinemia elicited by the 5-HT precursor, 5-hydroxytryptophan in mice: involvement of insulin.
Mechanisms for hyperleptinemia elicited by a serotonin (5-hydroxytryptamine, 5-HT) precursor, 5-hydroxytryptophan (5-HTP), were investigated. 5-HTP elicited apparent increases in serum leptin levels of mice. Administration of 5-HTP did not alter expression of leptin mRNA in white adipose tissues. Furthermore, neither 5-HTP nor 5-HT increased leptin secretion from isolated fat pads of mice. Since insulin is known to enhance leptin release, involvement of insulin in 5-HTP-induced hyperleptinemia was examined. 5-HTP significantly elevated serum insulin levels. In mice treated with streptozotocin, which depletes insulin, 5-HTP did not increase serum leptin levels. These results suggest that hyperinsulinemia participates the elevation of serum leptin levels elicited by 5-HTP.
Yamada
Jun
J
Department of Pharmacology, Kobe Pharmaceutical University, Motoyamakita-machi, Higashinada, Kobe 658-8558, Japan. j-yamada@kobepharma-u.ac.jp
Sugimoto
Yumi
Y
Ujikawa
Masanori
M
Goko
Hideki
H
Yagura
Tatsuo
T
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001545:Benserazide / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D007274:Injections, Intraperitoneal; D007328:Insulin / Q000502:physiology*; D020738:Leptin / Q000097:blood* / Q000235:genetics; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012701:Serotonin / Q000494:pharmacology; D018490:Serotonin Agents / Q000494:pharmacology; D013997:Time Factors
D007328:Insulin; D020738:Leptin; D012333:RNA, Messenger; D018490:Serotonin Agents; D012701:Serotonin; D001545:Benserazide; D006916:5-Hydroxytryptophan