CART peptide: central mediator of leptin-induced adipose tissue apoptosis?
Because of connections between CART peptide containing neurons and the sympathetic nervous system (SNS) and the possible role of the SNS in leptin-induced adipose apoptosis, CART may act as a downstream effector of leptin-induced adipose apoptosis. Male Sprague-Dawley rats received continuous intracerebroventricular (i.c.v.) infusion for 4 days of either artificial cerebrospinal fluid (aCSF, 12 microl/day), leptin (15 microg/day), or CART55-102 at 2.4 microg/day (CART2.4) or 9.6 microg/day (CART9.6). Food intake (FI) was decreased 10.8% for CART2.4, 41.9% for CART9.6 and 33.4% for leptin (p<0.05). CART9.6 and leptin reduced meal size and meal number. Body weight (BW) was reduced by CART9.6 (14.6%) and leptin (11.6%) (p<0.05), but not by CART2.4. CART9.6 and CART2.4, but not leptin, caused hypothermia, and CART9.6 inhibited physical activity (p<0.05). Epididymal, inguinal and retroperitoneal fat pad weights were reduced (p<0.05) by both CART treatments and leptin; CART9.6 also reduced gastrocnemius muscle weight (18.1%, p<0.05). Leptin, but not CART, increased serum free fatty acid concentrations by 31.1% (p<0.05) and increased adipose apoptosis by 48% (p<0.05). These data show that although leptin and CART55-102 have some similar actions, CART55-102 is probably not a mediator for leptin-induced adipose apoptosis in the brain.
Choi
Yang-Ho
YH
Department of Animal and Dairy Science, University of Georgia, 444 Animal Science Complex, Athens, GA 30602-2771, USA.
Della-Fera
Mary Anne
MA
Li
ChangLong
C
Hartzell
Diane L
DL
Little
Dianne E
DE
Kuhar
Michael J
MJ
Baile
Clifton A
CA
D000273:Adipose Tissue / Q000166:cytology* / Q000187:drug effects*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001831:Body Temperature / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005247:Feeding Behavior / Q000187:drug effects; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D020738:Leptin; D009419:Nerve Tissue Proteins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein