Age-related effects of nutritional vitamin B6 deficiency on B6-dependent enzymes of glutamate, gamma-aminobutyrate and glutamine systems in the rat brain

Abstract

Effect of nutritional vitamin B6 deficiency on the activities of enzymes-glutamic acid decarboxylase (GAD), gamma aminobutyric acid transaminase (GABA-T), aspartate amino-transferase (AsAT), alanine aminotransferase (AlAT) and glutamotransferase (GT) was studied in the rat brain of different age groups. Deficiency was induced at one day (group 1), 21 days (group 2), three months (group 3), 12 months (group 4) and 24 months (group 5) for a period of 3-10 weeks. When the holo and apoenzyme levels were compared in control and B6 deficient rats, it was found that GAD, GABA-T, AsAT and AlAT holoenzyme levels were significantly lower in the deficient rats of all the five groups whereas the level of GT holoenzyme was low only in group 1, the other groups did not show any significant change. GAD apoenzyme level was significantly higher in the deficient animals of group 1 and 2 while the reverse was true for GABA-T apoenzyme and no significant variation was seen in the older groups. It is interesting to note that the level of AsAT apoenzyme was significantly low in older age groups (4, 5) as a function of B6 deficiency, while AlAT and GT apoenzymes were not affected in any age group studied.