Metabolism of Glycogen in the Skin and the Effect of X-rays

Abstract

A method for isolating highly purified glycogen from dog skin is described. After perfusion of surviving isolated dog skin with C/sup 14/-labeled glucose, pure radioactive glycogen was recovered. De novo biosynthesis of glycogen in the skin was demonstrated and shown to be a rapid and continuous process. Attempts were made to follow changes in C/sup 14/-glucose uptake into glycogen in skin under the influence of x irradiation, which suppresses skin metabolism. The thigh of dogs was irradiated in vivo with 800 r. After 24 hr the skin flaps of both thighs, irradiated and non-irradiated, were perfused under identical conditions with blood or saline containing C/sup 14/-glucose. In all experiments the glucose uptake into glycogen was found to be significantly greater in the irradiated side. It was postulated that the effect is due to a radioinduced alteration in the relative rates of synthetic and degradative pathways. The inner thigh was irradiated in vivo with a single erythema dose. The increase of C/sup 14/-glucose uptake into glycogen started 18 hr after irradiation, reached a maximum at approximates 24 hr, and lasted for about 24 hr longer. It was concluded that phosphorylase activity in skin is weakened after irradiation; at the same timemore » there is an increase of glycogen synthetase activity. Ultraviolet irradiation with a mercury vapor lamp was found to have a similar effect to x rays, 24 hr after irradiation with a minimal erythema dose. The results show that glycogen turnover must be clearly distinguished from glycogen accumulation. (TCO)« less