Relationship of the activity of the bone isoenzyme of serum alkaline phosphataseto urinary hydroxyproline excretion in metabolic and neoplastic bone diseases

Abstract

A significant correlation between the activity of the bone isoenzyme or serum alkaline phosphatase and the urinary hydroxyproline excretion in osteomalacia, osteoporosis, primary hyperparathyroidism with osteo‐dystrophy, Paget's disease, secondary bone tumours, and in a control group was found (P< 0.001). This close correlation was not observed between these variables in patients with active acromegaly. Diagnosis determined from these indices of formation and turnover of bone matrix agreed with that established by histological and histochemical examination of bone, by X‐ray investigation of the skeleton, and by the radionuclear ⁸⁵Sr test. The relationship between the activity of bone isoenzyme and urinary hydroxyproline excretion differed in metabolic bone diseases with a high bone turnover, in patients with osteoporosis and in patients with early osteoclastic bone metastases.