Effect of cortisone and age on the hydroxyproline and proline concentrations of blood and urine in the rat.

Abstract

Hydroxyproline and proline form almost one-third of collagen. Moreover, a small amount of hydroxyproline has been found only in elastin. Hence, hydroxyproline has been used in the investigation of collagen. Stetten (1949) suggested that the hydroxyproline of collagen does not originate from the free hydroxyproline of blood but from the proline that is not oxidised before the peptide level. In this respect proline is closely related to the metabolism of hydroxyproline. The effect of cortisone on protein metabolism is considered to be catabolic or anti-anabolic (e.g., Albright, 1942, Ingle, 1950, Hoberman, 1951, Clark, 1953). This causes, for instance, the decrease in body weight and the increase in urinary nitrogen excretion seen after large doses of cortisone (Clark, 1953). The above observations have been found to concern the carcass protein rather than the structural, e.g., collagen (Kochakian & Robertson, 1951, Silber & Porter, 1952). Roberts et al. (1951) observed that cortisone