Studies of gamma-glutamyltransferase activity in the brain tissue post mortem

Our experiments showed that the activity of gamma-glutamyltransferase (gamma-GT) did not remarkably change in homogenates of mouse, rat, and bovine brains during the first four days post mortem. In the course of that period, the brain microvessels also retained their gamma-GT activity. gamma-GT of microvessels from bovine brain cortex, solubilized with sodium deoxycholate, was eluted in the void volume Vo when chromatographed on a Sephadex G-200 column with the detergent Triton X-100. In human post mortem brains, the specific activity of gamma-GT in choroid plexi was found to be about five times higher than that in the cerebral cortex, white matter, basal ganglia, pons, and cerebellum but about four times lower than that in the microvessels obtained from the studied brain regions. Our findings suggest that it is possible to study the components of the blood-brain barrier on material from deceased subjects.