Sensitivity of ob/ob mice to leptin-induced adipose tissue apoptosis.
OBJECTIVE
ob/ob mice have increased sensitivity to many of leptin's effects. The primary objective of this experiment was to determine whether ob/ob mice demonstrated increased sensitivity to leptin-induced adipose tissue apoptosis.


METHODS
Fifteen-week-old female ob/ob and Ob/? mice received 0 (saline), 2.5, or 10 microg/d leptin for 14 days through subcutaneous (sc) osmotic minipumps. Food intake (FI), body temperature, physical activity, and body weight were measured daily. Body composition and weights and adipose tissue apoptosis (percentage DNA fragmentation) of inguinal, parametrial, and retroperitoneal fat pads were determined at the end of the study.


RESULTS
FI decreases were more pronounced in ob/ob. Leptin (10 microg/d) decreased total FI 71% in ob/ob and 34% in Ob/? (p < 0.05). Body weight was decreased by both doses of leptin in ob/ob (p < 0.01) but was unchanged in Ob/?. Leptin increased body temperature in ob/ob but not in Ob/?. Physical activity was increased 400% by 10 microg/d leptin in ob/ob (p < 0.01) but decreased 13% in Ob/? (p < 0.01). Body fat content of ob/ob was reduced by both leptin doses, whereas only 10 microg/d leptin decreased body fat in Ob/?. Fat pad weights were decreased similarly by leptin in both genotypes. However, apoptosis was increased by leptin in all three fat pads in ob/ob, whereas Ob/? showed significant increases only in retroperitoneal.


CONCLUSIONS
ob/ob mice had greater overall sensitivity to leptin. Although ob/ob mice appeared to be more sensitive than Ob/? mice to leptin-induced adipose tissue apoptosis, there were differences among adipose depots in responsiveness to leptin-induced apoptosis.
Della-Fera
Mary Anne
MA
Department of Animal and Dairy Science, University of Georgia, Athens, Georgia 30602-2771, USA.
Choi
Yang-Ho
YH
Hartzell
Diane L
DL
Duan
Juihua
J
Hamrick
Mark
M
Baile
Clifton A
CA
D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001823:Body Composition / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D007328:Insulin / Q000097:blood; D050152:Intra-Abdominal Fat / Q000187:drug effects; D020738:Leptin / Q000097:blood / Q000494:pharmacology*; D051379:Mice; D008820:Mice, Obese; D009043:Motor Activity / Q000187:drug effects
D007328:Insulin; D020738:Leptin