Human osteogenic sarcoma: fine structural localization of alkaline phosphatase

The localization of alkaline phosphatase in eight osteogenic sarcomas of osteoblastic. chondroblastic, and fibroblastic type was investigated at the fine structural level using beta-glycerophosphate as substrate and lead as capturing ion. Final product marking localization of alkaline phosphatase was deposited over plasma membranes and associated subplasmalemmal vesicles and vacuoles in various types of osteoblastlike, chondroblastlike, and fibroblastlike cells as well as certain multinucleated giant cells. Presence of L-homoarginine or L-tetramisole in the incubation medium, and incubation at 65 degrees C, prevented the deposition of final product, suggesting that the enzyme studied was "bone specific." The evidence obtained was compatible with the notion that the different cells showing presence of reaction product were functionally and histogenetically closely related and all were likely to be capable of bone production.