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BRAIN 4‐AMINOBUTYRATE
Author(s) -
Sims K. L.,
Witztum J.,
Quick Colleen,
Pitts F. N.
Publication year - 1968
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1968.tb08965.x
Subject(s) - transaminase , period (music) , enzyme , biology , medicine , endocrinology , central nervous system , enzyme assay , specific activity , chemistry , biochemistry , physics , acoustics
— A systematic study was made of aminobutyrate transaminase (4‐aminobutyrate: 2‐oxoglutarate aminotransferase, I.U.B.2.6.1.19) in the developing rat brain. Assays of enzymic activity were made in whole brain of seven to twenty‐one animals at each day of age from birth to day 30. The numerous analyses allowed statistical treatment and recognition of an abrupt change in the rate of synthesis of aminobutyrate transaminase, as judged by activity/g wet wt., beginning at day 12. From birth through day 11 there was a linear increase of low slope in enzymic activity, from day 12 through day 26 there was a linear increase of markedly increased slope. During the first period γ‐aminobutyrate increased from 14 to 25 m‐moles/kg fresh wt./hr; during the second the increase was from 25 to 113. The change of slope of linear increase in rat brain aminobutyrate transaminase began abruptly midway in the ‘critical period’ of rat brain development which extends roughly from day 10 to day 14. The onset of peak increase of rat brain succinate semialdehyde dehydrogenase (I.U.B.1.2.1.16) by contrast, occurred at day 6, heralded the ‘critical period’, and preceded by 6 days the onset of peak increase of the transaminase. These time‐locked changes in rate of increase of two enzymes of a biochemical pathway uniquely functional in neural tissue may be of significance in determining the development of the nervous system in the young animal.