Effect of gamma-irradiation on the uptake and digestion of 125I-labeled bovine serum albumin by rat visceral yolk sac cultured in vitro.

The effect of gamma-irradiation on a major nutritional function of the yolk sac (the uptake and digestion of macromolecular materials) was studied in rat visceral yolk sacs cultured in vitro being used 125I-labeled bovine serum albumin (RISA) as the tracer protein. The uptake of RISA (per g wet weight) by rat yolk sacs irradiated with doses of 5-80 Gy was essentially the same as that in the unirradiated control yolk sacs. There were no significant differences in yolk sac uptake of RISA with respect to the radiation doses or to culture period up to 18 hours after irradiation. External gamma-irradiation with 10-80 Gy does also had no effect on the extracellular release of 125I from yolk sacs which had been taken it up as RISA. The ratios of the activity in ultrafiltrates of the medium to the total activity in the medium were slightly higher at doses of 40 and 80 Gy.