LEPTIN regulates adiposity by reducing caloric intake and increasing energy
expenditure. Because loss of body weight is common during infectious, neop
lastic, and autoimmune diseases of the central nervous system, we examined
whether an injection of lipopolysaccharide (LPS) into the lateral cerebral
ventricle increases circulating leptin levels in fasted mice. Centrally inj
ected LPS (100 ng) induced a two-fold elevation in plasma leptin 6, 12, and
18 h post-injection. Peripheral injection of the same dose of LPS did not
affect leptin secretion. This suggests that inflammatory stimuli localized
in the CNS are sufficient to induce leptin secretion in the periphery. The
induction of leptin by inflammatory stimuli in the brain may be part of a f
eed-back loop that contributes to anorexia and cachexia in many CNS-oriente
d diseases. (C) 1999 Lippincott Williams & Wilkins.