Prenatal human brain development. II. Studies on malate dehydrogenase.

Malate dehydrogenase (MDH) activity was analyzed in the CNS of 43 unaffected human fetuses aged 18--42 weeks of gestation. Regional differences in the levels of activity were observed at every age. MDH activity rises during this period in all areas, but the increase occurs prior to the 30th week in brain stem and spinal cord, and later in the other regions. MDH activity distribution into cytoplasmic and particulate fractions does not change throughout prenatal life, remaining essentially similar for the cerebral lobes, cerebellum and spinal cord. In the adult brain, however, the pattern is shifted towards a predominance of MDH activity in the cytoplasmic fraction of the spinal cord.