Enzymatic maturation of mouse cerebral neocortex in vitro and in situ

The developmental profiles of the activities of the X chromosome-linked enzymes α-galactosidase, hypoxanthine guanine phosphoribosyltransferase, and glucoses-phosphate dehydrogenase were studied in the brains of mice. X chromosome inactivation, which takes place at an early stage of development, led to identical enzyme activities in females and males between the 15th day of gestation and the 64th day after birth. The enzyme activities were also studied after an X-ray dose of 3 times 1.05 Gy, delivered on gestational days 11,12 and 13. Treatment with this dose, but not with 3 times 0.95 Gy or 1.15 Gy, respectively, was followed by the death of predominantly female offspring within 2 days after birth. The assumption that the reason for this might be a reactivation of inactive female X chromosomal genes in brain cells was tested in the present experiment. There were marked radiation-induced alterations of the activities of the above-mentioned enzymes. However, sex differences of these enzyme activities were not found after the irradiation treatment. A participation of X chromosome reactivation in the elevated mortality of female offspring is therefore unlikely.

Section: Resultscontrasting

confidence: 55%

Developmental Patterns of Three X Chromosomal Enzyme Activities in the Brains of Female and Male Mice

Weber¹,

Schmahl

1982

“…Human hemispheres and cerebellum show closely parallel trends in LDH activity devel opment to those previously reported by other authors in rat cerebellum [15,25], mouse cere bral neocortex [16] and rat cerebral cortex [14], The accelerated increases in LDH activity observed during the last period of gestation resemble those occurring postnatally in the rat at about days [8][9][10][11][12][13][14][15].…”

Section: Development Of Ldh Activitysupporting

confidence: 66%

Prenatal Human Brain Development

Chabás¹,

Briones²,

Sabater³

1979

The activity of lactate dehydrogenase (LDH) and its isozyme composition were analyzed in 41 unaffected human fetal brains of 18–42 weeks of gestation. Regional differences either in the levels of activity or in the patterns of development were observed. Throughout the 24-week period, the highest LDH activity was found in the spinal cord and the brain stem. Activity rises with age in all regions and, as compared to other developing structures, the cerebellum accounts for the most marked activity change. The LDH isozyme pattern does not show significant regional differences and, in any particular area, isozyme distribution does not change with developing age.

“…Profiles of maturation of MDH in the human do not differ essentially from those reported in animal species [15,16,19], dif ferences being restricted to the age at which activity rises maximally. In rat and mouse cere bral cortex the greatest rate of change in M DH activity occurs between days 8 and 14, corre sponding to the period of maximum growth spurt described by Davison and Dabbing [10].…”

Section: Discussionmentioning

confidence: 66%

“…Previous reports have demonstrated that brain MDH activity increases during the onto genesis of different animal species [14][15][16] and although some authors find no electrophoretic changes of the isozyme distribution pattern during development [5. 18], an increase of 115'\, in mitochondrial MDH specific activity, compared to a 53"0 increase in the super natant enzyme, has been found from birth to day 21 in the rat brain [Chabds and Costa, unpublished data].…”

Section: Introductionmentioning

confidence: 99%

Prenatal Human Brain Development

Chabás¹,

Briones²,

Sabater³

1980

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.