Fasting and leptin modulate adipose and muscle uncoupling protein: divergent effects between messenger ribonucleic acid and protein expression. Endocrinology 1999 Apr;140(4):1511-9
Date
03/31/1999Pubmed ID
10098482DOI
10.1210/endo.140.4.6668Scopus ID
2-s2.0-0032980686 (requires institutional sign-in at Scopus site) 99 CitationsAbstract
Leptin is believed to act through hypothalamic centers to decrease appetite and increase energy utilization, in part through enhanced thermogenesis. In this study, we examined the effects of fasting for 2 days and exogenous s.c. leptin, 200 microg every 8 h for 2 days, on the regulation of uncoupling protein (UCP) subtypes in brown adipose tissue (BAT) and gastrocnemius muscle. Northern blot analysis (UCP-1) and ribonuclease protection (UCP-2 and 3) were used for quantitative messenger RNA (mRNA) analysis, and specific antibodies were used to measure UCP-1 and UCP-3 total protein expression. Leptin, compared with vehicle, did not alter BAT UCP-1 or UCP-3 mRNA or protein expression when administered to normal ad libitum fed rats. Fasting significantly decreased BAT UCP-1 and UCP-3 mRNA expression, to 31% and 30% of ad libitum fed controls, respectively, effects which were prevented by administration of leptin to fasted rats. Fasting also significantly decreased BAT UCP-1 protein expression, to 67% of control; however, that effect was not prevented by leptin treatment. Fasting also decreased BAT UCP-3 protein, to 85% of control, an effect that was not statistically significant. Fasting, with or without leptin administration, did not affect BAT UCP-2 mRNA; however, leptin administration to ad libitum fed rats significantly increased BAT UCP-2 mRNA, to 138% of control. Fasting significantly enhanced gastrocnemius muscle UCP-3 mRNA (411% of control) and protein expression (168% of control), whereas leptin administration to fasted rats did not alter either of these effects. In summary, UCP subtype mRNA and protein are regulated in tissue- and subtype-specific fashion by leptin and food restriction. Under certain conditions, the effects of these perturbations on UCP mRNA and protein are discordant.
Author List
Sivitz WI, Fink BD, Donohoue PAMESH terms used to index this publication - Major topics in bold
Adipose TissueAnimals
Blotting, Northern
Carrier Proteins
Fasting
Gene Expression
Ion Channels
Leptin
Male
Membrane Proteins
Membrane Transport Proteins
Mitochondrial Proteins
Muscle, Skeletal
Proteins
RNA, Messenger
Rats
Rats, Sprague-Dawley
Uncoupling Agents
Uncoupling Protein 1
Uncoupling Protein 2
Uncoupling Protein 3
