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Abstract

We studied the effect of mandibular fracture and denervation on [(14)C]carbonate metabolism. A new index (bone/plasma relative radioactivity) reflecting the ratio between (14)C incorporation into bone and plasma was proposed. The percentage of label incorporation and bone/plasma relative radioactivity were measured from the 5th minute to the 192nd hour after intraperitoneal injection of labeled carbonate to 1-2-month-old albino rats. We revealed a biphasic reaction: rapid accumulation and elimination of the isotope form the bone; and slow accumulation followed by slow accumulation and elimination. Changes in carbonate metabolism after bone fracture corresponded to phases of reparative osteogenesis. At the stage of cellular-and-fibrous callus accumulation of labeled carbonate dominated over its elimination. At the stage of chondroid callus elimination dominated over accumulation. At the stage of primary osseous callus elimination dominated over accumulation, but did not surpass the control level. After fracture the index of bone/plasma relative radioactivity underwent general changes that were most pronounced in the zone of trauma. After denervation this index also decreased.