Parathyroid Influence on Removal of Hydroxyproline by Peritoneal Lavage in the Rat,∗

Summary

Utilizing the technique of peritoneal lavage, levels of hydroxyproline and calcium in lavage fluid and plasma were studied in intact and parathyroidectomized rats with and without concomitant nephrectomy. A limited characterization of the molecule containing this imino acid also was made by gel filtration. Levels of free hydroxyproline removed from parathyroidectomized rats were consistently lower than from intact rats. These differences were greatly magnified by concomitant nephrectomy. However, the endogenous parathyroid stimulation produced by nephrectomy also resulted in an increase in bound hydroxyproline which is detectable only after hydrolysis of the lavage fluid or plasma. The results indicate that hydroxyproline levels in plasma and lavage fluid are parathyroid-dependent and can be correlated with calcium removal under the conditions of parathyroidectomy and/or nephrectomy. These studies further suggest that the breakdown of bone under the influence of parathyroid hormone includes both its organic and inorganic components.