Role of neonatal hyperleptinaemia on serum adiponectin and suppressor of cytokine signalling-3 expression in young rats.
Previously we had shown that neonatal leptin treatment programmes for both hyperleptinaemia and hyperinsulinaemia, which lead to leptin resistance and low expression of the hypothalamic leptin receptor (OB-Rb) of rats aged 150 d. Here we investigated in young post-weaned rats (age 30 d) if leptin treatment during lactation induces leptin and insulin resistance and if those changes are accompanied by changes in the suppressor of cytokine signalling-3 (SOCS-3) expression and serum adiponectin concentration. After delivery, the pups were divided into two groups: (1) a leptin group (Lep) that were injected with leptin daily (8 microg/100 g body weight subcutaneously) for the first 10 d of lactation; (2) a control (C) group, receiving saline. After weaning (day 21), body weight was monitored until the animals were age 30 d. They were tested for food intake in response to either leptin (0.5 mg/kg body weight intraperitoneally) (CL, LepL) or saline (CSal, LepSal) when they were aged 30 d. The CL group showed lower food intake, but no response was observed in the LepL group, suggesting leptin resistance. The Lep group had hyperleptinaemia (five-fold), hyperinsulinaemia (+42.5%) and lower levels of serum adiponectin (-43.2%). The hypothalamic expression of OB-Rb was lower (-22%) and SOCS-3 was higher (+52.8%) in the Lep group. We conclude that neonatal leptin treatment programmes for leptin resistance as soon as 30 d and suggests that SOCS-3 appears to be of particular importance in this event. In the Lep group, the lower serum adiponectin levels were accompanied by higher serum insulin, indicating a probable insulin resistance.
Passos
Magna Cottini Fonseca
MC
Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro 20550-030, RJ, Brazil. magna.cottini@pq.cnpq.br
Toste
Fabiane Pereira
FP
Dutra
Sheila Cristina Potente
SC
Trotta
Paula Affonso
PA
Toste
Fernanda Pereira
FP
Lisboa
Patrícia Cristina
PC
de Moura
Egberto Gaspar
EG
D052242:Adiponectin / Q000097:blood*; D000818:Animals; D000831:Animals, Newborn / Q000097:blood* / Q000254:growth & development; D001786:Blood Glucose / Q000032:analysis; D015153:Blotting, Western / Q000379:methods; D001823:Body Composition; D001835:Body Weight; D004351:Drug Resistance; D004435:Eating; D005260:Female; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000097:blood*
D052242:Adiponectin; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; C491410:Socs3 protein, rat; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins