Effects of subcutaneous leptin injections on hypothalamic gene profiles in lean and ob/ob mice.
OBJECTIVE
Leptin-deficient ob/ob mice are more sensitive to exogenous leptin than lean mice and leptin treatment normalizes many of the phenotypic characteristics of ob/ob mice. The primary objective of this experiment was to investigate whether this altered leptin sensitivity in ob/ob mice was reflected in the hypothalamic mRNA profile.


METHODS
Fifteen-week-old female ob/ob and lean mice were treated with 14 days of subcutaneous (sc) infusion of phosphate-buffered saline (PBS) or leptin (10 mug/d) using osmotic pumps. Real-time Taqman reverse transcription polymerase chain reaction (RT-PCR) (ABI Microfluidic cards) was used to quantitatively compare the mRNA levels of selected hypothalamic genes in these groups.


RESULTS
Hypothalamic mRNA levels for ob/ob control mice were higher for agouti-related protein (AGRP), neuropeptide Y (NPY), and arginine vasopressin (AVP), and lower for cocaine- and amphetamine-regulated transcript (CART), cAMP response element binding protein (CREB)-1, proopiomelanocortin (POMC)-1, and urocortin (UCN)-3 compared with lean controls. In leptin-treated ob/ob mice, hypothalamic mRNA levels were reduced for NPY, AGRP, AVP, and increased for suppressor of cytokine signaling 3 (SOCS3) compared with ob/ob controls. Leptin treatment dramatically up-regulated hypothalamic mRNA level of POMC1 in both lean and ob/ob mice. Strong correlations were observed between hypothalamic Janus kinase 2 (JAK2) and CREB1, STAT3 and CREB1, JAK2 and STAT3, NPY and AVP in all samples.


CONCLUSIONS
ob/ob and lean mice have different hypothalamic mRNA expression patterns (particularly those of feeding-related genes), and selected genes in ob/ob mice are more sensitive to exogenous leptin stimulation compared with lean mice.
Duan
Jiuhua
J
Department of Animal and Dairy Science, University of Georgia, Athens Georgia 30602-2771, USA.
Choi
Yang-Ho
YH
Hartzell
Diane
D
Della-Fera
Mary Anne
MA
Hamrick
Mark
M
Baile
Clifton A
CA
D000818:Animals; D001127:Arginine Vasopressin / Q000235:genetics / Q000378:metabolism; D001835:Body Weight / Q000235:genetics; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004435:Eating / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007279:Injections, Subcutaneous; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism; D020738:Leptin / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice; D008820:Mice, Obese; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D009765:Obesity / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism; D013851:Thinness / Q000378:metabolism*; D054832:Urocortins / Q000235:genetics / Q000378:metabolism; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D020738:Leptin; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C491411:Socs3 protein, mouse; C494087:Stat3 protein, mouse; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D054832:Urocortins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D001127:Arginine Vasopressin; D011333:Pro-Opiomelanocortin; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2