Synthesis and turnover of collagen precursors in rabbit skin

Abstract

The rate of synthesis of [14c] hydroxyproline by rabbit skin was studied in vitro and in vivo. The soluble collagen fractions were shown to have a very rapid turnover. The 0.15 [image]-sodium chloride-extractable collagen showed t1/2 values of 1.2 hr. in vitro and 12 hr. in vivo. The 0.5 [image]-sodium chloride-ex-tractable collagen exhibited at t1/2 value of 20 hr. in vivo. Under the conditions used it was not possible to obtain radioactive insoluble collagen in vitro. A significant amount of soluble collagen is lost be-fore it becomes insoluble. These observations may help to explain why large amounts of peptide-bound hydroxyproline appear in the urine during periods of rapid collagen synthesis.