Effects of whole-body X-irradiation on some aspects of collagen metabolism in the rat

Whole-body exposure of adult rats to X rays at sublethal or lethal doses causes a decrease in hydroxyproline levels in urine and skeletal muscle. Similarly, reduction in the excretion of labeled hydroxyproline in urine following intraperitoneal injection of 14C-proline, may be attributed to impaired in vivo hydroxylation of proline. Incorporation of administered 14C-proline into 14C-hydroxyproline and its distribution in different metabolic forms of collagen in skeletal muscle and skin are markedly reduced in X-irradiated rats. These suggest impaired hydroxylation of proline. However, in vitro proline hydroxylase activity in liver is not affected by radiation treatment. Decreased endogenous oxygen consumption, as observed in liver homogenates of X-irradiated rats, may be one of the factors which affect in vivo proline hydroxylation