Late effects in the central nervous system. A study of biochemical alterations after local exposure of the rat brain to 2 krd

The brain area of female rats three months of age was exposed to 2 krd of X rays, and various biochemical parameters were determined as well as NAD(H) in vivo fluorescence of the brain surface after time intervals from one day to 18 months. During the early period, an increase in the uptake of α aminobutyrate C ¹⁴ (AIB) and a temporary depression in β glucuronidase and cathepsin activity followed by an activation at one month was seen. Somewhat later, acid phosphatase increases. During the intermediate period, DNA and serotonin content and AIB uptake by brain increase, whereas AIB uptake by heart and muscle decreases. A fall in sialic acid content is also noted at this time. During the late phase collagen increases, AIB uptake by brain and liver decreases. No changes were found with respect to NAD(H) fluorescence and its response to breathing of low oxygen concentrations.