Acute effect of leptin and ghrelin injection on postprandial glycogen and lipid synthesis in rats.
OBJECTIVE
The study was designed to investigate the immediate (1 h) effect of leptin and ghrelin injection on in vivo postprandial hepatic glycogen and lipid synthesis.


METHODS
Adult Sprague-Dawley male rats were fed a semisynthetic control diet ad libitum. Overnight-fasted rats were gavaged with 4 ml of water containing 1.25 g of the diet and immediately injected intraperitoneally with 4 mCi of (3)H(2)O. After 1 h, rats were either intraperitoneally injected with saline (control), leptin (20 microg/rat) or ghrelin (10 microg/rat) and sacrificed 1 h later. Blood, liver and epididymal fat pads (EFP) were taken for analysis.


RESULTS
Plasma triglyceride level was higher in the leptin group compared to control. Leptin injection reduced hepatic glycogen synthesis while glycogen accumulation was not affected and ghrelin injection did not affect hepatic glycogen synthesis. Both hepatic and EFP lipogenesis were not affected by leptin or ghrelin.


CONCLUSIONS
Leptin and ghrelin administration had no immediate effect on hepatic and adipose tissue lipogenesis. Leptin reduced in vivo postprandial hepatic glycogenesis and increased plasma triglyceride level which may be due to reduced uptake by peripheral tissues. Thus, leptin was found to exert an immediate effect on lipid and carbohydrate metabolism unlike that of ghrelin.
Bassil
Maya S
MS
Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon.
Mrayati
Maha M
MM
Hwalla
Nahla C
NC
Obeid
Omar A
OA
D000273:Adipose Tissue / Q000187:drug effects; D000818:Animals; D054439:Ghrelin; D007274:Injections, Intraperitoneal; D020738:Leptin / Q000008:administration & dosage / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects*; D008112:Liver Glycogen / Q000096:biosynthesis*; D008297:Male; D023421:Models, Animal; D036361:Peptide Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D019518:Postprandial Period; D051381:Rats; D017207:Rats, Sprague-Dawley
D054439:Ghrelin; D020738:Leptin; D008112:Liver Glycogen; D036361:Peptide Hormones