Degradation and turnover of collagen in the mouse skin and the effect of whole body x-irradiation.

Abstract 1. 1. Male mice were given L -[ 3 H]proline intraperitoneally at 4 weeks of age. The total radioactivity of hydroxyproline in the whole body skin increased with time up to the 6th week after the injection, and then gradually decreased to 19.8% of the peak value in the following 50 weeks. The half-life of the labeled skin collagen was calculated as 80 days in the mice at 18–30 weeks of age, 130 days at 30–45 weeks of age and 200 days at 45–60 weeks of age, respectively. 2. 2. The degredation of skin collagen in adult mice was accelerated by whole body exposure to a total of 900 or 1200 R X-ray. Exposure to 300 R 4 times resulted in a 30% increase in the degradation of labeled collagen in the 30–60-week-old mice. 3. 3. The total amount of collagen in the whole body skin was also significantly decreased by a total of 900 or 1200 R irradiation. 4. 4. The turnover rate of 1 M NaCl-soluble collagen was higher than that of insoluble collagen and this tendency was amplified by X-irradiation. 5. 5. The decrease in the solubility of skin collagen with ageing was accelerated by X-irradiation.