Unidirectional flux (clearance) across the placenta (A and B) and fetal accumulation of tracer per gram of fetus (C and D) of [14C]-methyl-d-glucose (A and C) and [14C]-MeAIB (B and D) in mice fed ad libitum (control, CT, filled columns) and undernourished by feeding 80% of control food intake (UN, open columns) at D16 and D19 of pregnancy. Mean litter clearance ±s.e.m. *Significant differences between CT and UN assessed by unpaired t test, P < 0.05 to P < 0.01. †Significant differences between age within treatment group, unpaired t test, P < 0.05 to P < 0.0001.