Comparative acute effects of leptin and insulin on gluconeogenesis and ketogenesis in perfused rat liver.
The acute effects of physiological levels of leptin (10 ng ml(-1)) and insulin (20 microU ml(-1)) on hepatic gluconeogenesis and ketogenesis were compared. Leptin or insulin alone decreased (p<0.05) the activation of hepatic glucose, L-lactate and urea production from L-alanine. However, the hepatic glucose production was not modified if leptin was combined with insulin. These results indicated that both, i.e. leptin and insulin, could promote a non-additive reduction in the rate of catabolism of L-alanine. However, in contrast with insulin (p<0.05), leptin did not inhibit the activation of hepatic glucose production from pyruvate or glycerol. On the other hand, activation of hepatic production of acetoacetate and beta-hydroxybutyrate from octanoate was not affected by leptin or insulin. Thus, our data demonstrate that the acute effect of leptin on hepatic metabolism was partially similar to insulin (activation of glucose production from L-alanine and activation of acetoacetate or beta-hydroxybutyrate production from octanoate) and partially different from insulin (activation of glucose production from pyruvate or glycerol).
Borba-Murad
Glaucia Regina
GR
Department of Physiological Sciences, State University of Londrina, 86051-990, Londrina, PR, Brazil.
Mario
Erica Guilhen
EG
Bassoli
Bruna Kempfer
BK
Bazotte
Roberto Barbosa
RB
de Souza
Helenir Medri
HM
D000409:Alanine / Q000378:metabolism; D000818:Animals; D019540:Area Under Curve; D002210:Caprylates / Q000378:metabolism; D005943:Gluconeogenesis / Q000502:physiology*; D005947:Glucose / Q000096:biosynthesis; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D007659:Ketones / Q000378:metabolism*; D019344:Lactic Acid / Q000096:biosynthesis; D020738:Leptin / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014508:Urea / Q000378:metabolism
D002210:Caprylates; D007328:Insulin; D007659:Ketones; D020738:Leptin; D019344:Lactic Acid; D019289:Pyruvic Acid; D014508:Urea; D005947:Glucose; C031492:octanoic acid; D000409:Alanine