Influence of Prenatal Hypoxia on Brain Development: Effects on Body Weight, Brain Weight, DNA, Protein, Acetylcholinesterase, 3-Quinuclidinyl Benzilate Binding, and In Vivo Incorporation of [14C]Lysine into Subcellular Fractions

Abstract: The influence of prenatal hypoxia on subsequent brain development in the young rat was investigated by examining body and brain weight, cerebral cortex wet weight, protein and DNA concentrations, acetylcholinesterase (AChE) activity, 3-quinuclidinyl benzilate (QNB)-binding levels, the relative amounts of protein in various subcellular fractions, and the in vivo incorporation of [¹⁴C]lysine into the protein of homogenate and subcellular fractions. Exposure of pregnant females to a mild hypoxia (9.1% Os, 10 h per day for the 9-11 days preceding birth) resulted in a reduced body weight in the pups at days 1 and 5 after birth; total cortical DNA was reduced but brain weight and protein content were unaffected, leading to a higher protein/DNA ratio in prenatally hypoxic pups. By 10 days of age these differences between prenatally hypoxic and control animals were no longer apparent. There were no differences between prenatally hypoxic and control animals in AChE and QNB binding per milligram cortex protein. The relative amount of synaptic membrane protein from the cerebral cortex was reduced at day 1 in prenatally hypoxic animals and the synaptic membrane fraction showed a higher level of incorporation of [¹⁴C]lysine on days 1, 5, and 10. The developmental profile of [¹⁴C]lysine incorporation showed a peak on day 10 which was higher in prenatally hypoxic rats. By 46 days after birth little difference could be found between prenatally hypoxic and control animals.