[The acute action of gamma radiation at a dose of 1 Gy on the enzymatic activity of serum ATPase and ADPase]. / Ostroe vozdeistvie gamma-izlucheniia v doze 1 Gr na fermentativnuiu aktivnost' syvorotochnoi ATFazy i ADFazy.

Studies were carried out to investigate the activity of ATPase and ADPase in rat blood serum after strong (137Cs) on the rate of 1 Gy. Rats were examined for various postirradiation periods up to 3 months. Two-fold decreasing of serum ATPase activity was recorded within the two weeks after gamma-irradiation. The rate of 3H-ADP enzymatic hydrolysis in the serum of irradiated animals remained unchanged as compared to controls.

Intraglomerular thrombotic tendency and glomerular ADPase. Unilateral impairment of ADPase elicits a proaggregatory microenvironment in experimental glomerulonephritis.

It has been proposed, predominantly from ex vivo studies, that glomerular ADPase may function as an antithrombotic principle within the rat kidney. Therefore, intraglomerular platelet aggregation was studied in vivo in rats after impairment of glomerular ADPase activity using local X-irradiation (20 Gy). Biochemical assays in suspensions of glomeruli obtained from rats 24 hours after local X-irradiation (group I) demonstrated a significant reduction in ADPase activity as compared to sham treated rats (group II; p less than 0.01). Cytochemical observations at the ultrastructural level showed that this reduction in glomerular enzyme activity represents in particular ADPase activity detectable in the basement membrane. Following X-irradiation, intraglomerular platelet aggregation was quantitatively studied in two groups of rats. Both groups received X-irradiation of the left kidney (20 Gy). Twenty-four hours after X-irradiation, animals received an intravenous injection of either 0.5 ml of saline (group III; N = 6) or 0.5 ml of heterologous nephrotoxic serum (NTS; group IV; N = 6). Subsequently, 24 hours after this injection, platelet aggregation in left kidneys was compared with aggregation in contralateral non-X-irradiated kidneys. The results showed that while X-irradiation per se did not induce intraglomerular platelet aggregation as compared with the contralateral kidney (0.20 +/- 0.08% versus 0.17 +/- 0.06% platelet aggregation/glomerulus), a significant increase in platelet aggregation could be demonstrated in X-irradiated kidneys in the early phase of nephrotoxic serum nephritis as compared with the contralateral nephritic kidney (2.45 +/- 0.66% versus 1.37 +/- 0.35% platelet aggregation per glomerulus; p less than 0.005). A potential effect of altered influx of inflammatory cells after X-irradiation could be excluded since no difference in H2O2 producing cells was observed between left and right kidneys. Thus, while ADPase impairment by X-irradiation does not induce platelet aggregation per se, it is clear that in proaggregatory conditions, like in NTS nephritis, the thrombotic tendency, due to decreased glomerular ADPase, is enhanced. These results demonstrate the functional significance of glomerular ADPase activity as an antithrombotic principle following platelet activation in vivo.