Ovariectomized prepuberal gilts were either fed to appetite (FA) or feed restricted to one-thirdof FA diet (RST) for 7 seven days. On day 8 blood samples were collected. Serumconcentrations of insulin (P<0.07), triiodothyronine (P<0.08), and thyroxine (P<0.04) werereduced in RST pigs. There was a treatment by time interaction (P<0.04) for non-esterifiedfatty acids levels, but $-hydroxybutyrate, luteinizing hormone (LH), and leptin concentrationswere unaffected by RST. RST failed to effect backfat leptin, long form leptin receptor,adipocyte fatty acid binding protein, CCAAT/enhancer binding protein-", or peroxisomeproliferator activated receptor-( 2 gene expression. FA gilts gained (P <0.001) more BW thanRST gilts but BF thickness was unchanged. These results may be related to the failure of RSTof this duration to influence subcutaneous BF. Thus, the leptin and LH response to RST mayrequire energy levels and (or) BF reduction reaching a putative inhibitory threshold.
