The Changes of Alkaline Phosphatase Activity and Inorganic Pyrophosphate Concentration in Compressed Bone

Abstract

The changes of alkaline phosphatase (Al-Pase) activity and inorganic pyrophos-phate (PPi) concentration in the rat sera and tibia under the several experimentalconditions were studied on to find out the metabolic changes in the compressed bone.1) A specific enzymatic fluorometric method for the determination of PPi was examined to apply to the many samples of very low concentration.2) The marked increase of PPi concentration and the decrease of Al-Pase activity in the sera and saliva after 30 min. of sodium pyrophosphate ingestion were found in spite of the high turn-over rate of PPi. The contrary change of Al-Pase suggested the consumption by large amount of PPi.3) The Al-Pase activities of rat sera wearing the compression apparatus were decreased at initial stage after operation and recovered to control level after 24 hours. PPi concentrations of these rat sera were increased 16 hours after operation and decreased thereafter. The reverse relation of Al-Pase and PPi was also revealed in this condition.4) The Al-Pase activities of the medial and distal parts of compressed tibia were ma rkedly increased up to 168 hours. The Al-Pase/DNA ratio also confirmed this results. Contrary, the Al-Pase activities of the compressed parts were lower than those of the control after24 hours.5) The PPi concentrations of the compressed tibia were decreased in 16 to 24 hoursin which Al-Pase activities were increased. At 168 hours after operation, PPi concentrations of compressed parts were higher than those of the control though those were almost the same in the medial parts and their control.6) The PPi/Al-Pase ratio made clear the difference in the compressed bone f rom theother parts. In 48 to 168 hours the PPi/Al-Pase ratio of compressed parts of tibia were markedly higher than those of the control.The significance of the Al-Pase and PPi in the metabolic changes of the compre ssedbone which is a very important problem in the prosthetic dentistry was disscussd.