Effects of x-irradiation on glycogenolysis, glycogenesis and gluconeogenesis in the rat

Abstract

In the x-irradiated and fasted rat, the liver undergoes, during the first 8–10 hr. postirradiation, a fall in glycogen similar to that seen in the nonirradiated, fasted rat. This is followed in the irradiated animal by a striking increase in the liver glycogen which reaches a maximum in about 50 hr. There follows a precipitous fall with the glycogen values reaching abnormally low values in 75–80 hr. A similar rapid rise and fall in the liver glycogen was seen when fasting preceded the irradiation. A comparable increase, but progressively smaller influence, is seen when the total body x-irradiation is decreased to 250 r. Blood-sugar values increased to high normal nonfasting levels during the period of fasting and simultaneous with excessive glycogen synthesis. The blood-sugar levels began falling as the liver glycogen values fell. Excess glucose is handled normally as indicated by tolerance tests. Adrenalectomy and hypophysectomy prevented these changes in the x-irradiated rats indicating a strong gluconeogenic influence. X-irradiation of one of a pair of parabiot rats produced this same glycogenic effect in the irradiated animal with a reflection of the effect in the nonirradiated animal of the pair.