Leptin reduces juvenile fat stores by altering the circadian cycle
of energy expenditure.
Stehling, Oliver, Heiko D[diaeresis]oring, Johann Ertl, Gerald
Preibisch, and Ingrid Schmidt.
Max-Planck-Institut, f[umlaut]ur physiologische und klinische
Forschung, W.G. Kerckhoff-Institut, Parkstr. 1, D-61231 Bad Nauheim,
FRG, Hoechst AG, Hoechst Marion Roussel, Therapeutic Area Research
Frankfurt, D-65926 Frankfurt, FRG
APStracts 3:0332R, 1996.
The recently identified hormone leptin (ob-protein) secreted by white
adipose tissue is widely thought to provide a feedback signal
limiting fat storage by decreasing food intake. By artificially
rearing leptin-treated and control littermates fed identical amounts
of milk, however, we show here that lean suckling-age rats treated
with recombinant murine leptin can reduce fat storage solely by
increasing energy expenditure. Continuous measurements of core
temperature and metabolic rate show that this increase is not uniform
throughout the day but is especially prominent in the morning, when
rat pups usually conserve energy by entering a torpor-like state.
Leptin's alleviation of hypometabolic, torpor-like states is thus not
restricted to cases of impaired hormone production but seems instead
to be a normal biological function independent of its effects on food
intake.
Received 26 July 1996; accepted in final form 27 August 1996.
APS Manuscript Number R439-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996