Nutrition and fetal brain maturation: II. Impact of maternal starvation on changing levels of acetylcholinesterase and enolase in vitro

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The impact of maternal starvation during Days 17–20 of gestation was examined in 20-day fetal rat brain tissue cultured for 6 days in MEM and 10% adult rat serum. Acetylcholinesterase (AChE) activities were consistently greater in fetal brain cell cultures from starved mothers. When fetal tissues from starved mothers were continuously exposed to 72-h fasted serum, AChE activities increased from 1.03±0.14 to 1.59±0.21 μmol/h/mg protein ( P<0.001). In fetal tissues from fed mothers, lower AChE activities were increased from 0.78±0.09 to 1.04±0.07 μmol/h/mg protein ( P<0.05) when 72-h fasted serum was used to replace the fed serum during incubation. When fetal brain cell cultures from fed mothers were exposed for 6 days to graded concentrations of fed serum (2.5–15%), the activities of AChE fell reciprocally from 1.34±0.10 to 0.82±0.12 μmol/h/mg protein ( P<0.05). The levels of AChE activity in tissues exposed to fasted serum were consistently greater, but fell similarly from 1.62±0.10 to 0.97±14 μmol/h/mg protein ( P<0.01), when serum concentrations were increased from 2.5 to 15%. AChE activities were 30% higher in tissues incubated with cycloheximide 10 −3 M ( P<0.02). Unlike AChE, fetal brain enolase activities were unaffected by maternal starvation. In fetal brain cell cultures from fed mothers, enolase fell from 1.85±0.10 to 1.37±0.12 μmol/min/mg protein following exposure to fasted instead of fed serum ( P<0.02). In fetal cultures from starved mothers, enolase activities were depressed similarly from 1.76±0.08 to 1.41±0.09 μmol/min/mg protein when fasted replaced fed serum ( P<0.02). Thus, the fetal brain cell cultures appear to maintain enzymatic realignments imposed by maternal starvation for at least 6 days. In addition, serum from fasted animals has significant growth inhibiting properties manifested by heightened activities of AChE and lower activities of enolase.