While serum leptin levels (ng/ml; Mean ± SE) did not change in DIO rats under SC diet (2.4 ± .3 vs. 2.6 ± 0.2 at 1 and 6 weeks; Fig. 3a), HF feeding for 1 week significantly increased (3.9 ± 0.2) and 6 weeks further elevated serum leptin (6.4 ± 0.3; p < 0.05). Here, LEP is linked to hydrops fetalis.