Melatonin inhibits fatty acid transport in inguinal fat pads of hepatoma 7288CTC-bearing and normal Buffalo rats via receptor-mediated signal transduction
La. Sauer et al., Melatonin inhibits fatty acid transport in inguinal fat pads of hepatoma 7288CTC-bearing and normal Buffalo rats via receptor-mediated signal transduction, LIFE SCI, 68(25), 2001, pp. 2835-2844
Melatonin inhibits fatty acid uptake and linoleic acid-dependent growth in
hepatoma 7288CTC in vivo in Buffalo rats. In this study we measured the eff
ects of melatonin on arteriovenous differences for fatty acids across ingui
nal fat pads in fed and fasted rats to determine if fatty acid transport in
white adipose tissue was also affected by melatonin. Intravenous infusion
of melatonin in fasted tumor-bearing rats in vivo simultaneously and rapidl
y inhibited both fatty acid release from fat pads and fatty acid uptake by
the tumors. Perfusion of fat pads in situ in normal rats with melatonin (0.
1 nM) inhibited fatty acid release (fasted rats) and uptake (fed rats). Fat
ty acid transport was restored by addition of any of the following: a melat
onin receptor antagonist (S 20928, 1.0 nM), pertussis toxin (0.5 mug/ml), f
orskolin (1 muM) or 8-Br-cAMP (10 muM). We conclude that fatty acid transpo
rt in inguinal fat pads requires cAMP and that melatonin inhibits this tran
sport via a melatonin receptor-mediated, G(i) protein-coupled signal transd
uction pathway. Melatonin has both anticachectic and lipid homeostatic acti
ons in the white adipose tissue of inguinal fat pads. (C) 2001 Elsevier Sci
ence Inc. All rights reserved.