Temporary changes in arylsulphatase activity in mouse liver after gamma-irradiation

Temporary changes in arylsulphatase (EC 3.1.6.1) activity in the liver of adult male Swiss mice after gamma-irradiation were studied. The animals were whole-body irradiated with a single dose of 10 Gy from a 60Co source, always at 19.00. The enzyme activity in crude liver homogenates was assessed every four hours during the 24-hour period, starting at 20.00. The enzyme activity with p-nitrocatechol sulphate as a substrate was related to mg of protein, gram of fresh tissue, and the whole organ weight. Protein concentration in the liver was calculated both per gram of fresh tissue and for the whole organ weight. The body and liver weights were also analysed. No fluctuations in the activity of arylsulphatase in the control mice were observed. Gamma-irradiated mice showed enzyme activity changes expressed in nkat per mg protein with a maximum at 4.00 and minimum at 20.00, twenty-five hours after irradiation. As compared with non-irradiated controls, the arylsulphatase activity calculated in nkat per g of fresh tissue and nkat per whole liver weight differed in irradiated animals which were killed at 4.00, while there was also a difference in the protein concentration in mg related to the whole organ weight in those killed at 12.00.