pituitary gland; hypothalamus; adipose tissue; animals; inbred stains; mice; intercellular signaling peptides; intercellular signaling proteins; angiopoietins; blood proteins; membrane proteins; protein isoforms; nuclear receptors; cytoplasmic receptors; transcription factors; RNA messenger; cytokines; northern blotting; reverse transcriptase polymerase chain reaction; food deprivation; males; adipokines