POMC expression in hypothalamus and placenta of ad libitum fed and food-restricted rats. Relative POMC mRNA levels in (A) hypothalamus and (B) placenta from ad libitum fed or food-restricted female rats at different pregnancy stages (12, 16 and 21 days). Relative mRNA levels were normalized to ad libitum fed (control) as 1. *: P < 0.05 vs. ad libitum 12d; **: P < 0.01 vs. ad libitum 12d; ***: P < 0.001 vs. ad libitum 12d; ##: P < 0.01 vs. ad libitum 16d; ###: P < 0.001 vs. ad libitum 16d; !!: P < 0.01 ad libitum 21d vs. food-restricted 21d.