The effect of tenotomy on bone weight was studied in order to investigate the mechanism of bone formation in terms of quantitative and qualitative difference by exercise stimulus and individual differences in bone formation. A/J, NZB/N, NZW/N and AKR/N inbred mice were used for observing the influence of genomic factors on bone weight following tenotomy. The tendon of the gastrocnemius muscle of the right leg was transected 2 mm proximal to the upper margin of the retinaculum. The tenotomized animals behaved nor-mally without visible disability. The tibia was weighed on the 7th day after the operation. Tibia weight and tibia weight per unit body weight for the tenotomized limb were significantly lower than those of the control limb in NZB/N, NZW/N and A/J strains.
　Therefore it was concluded that this tenotomy model would be useful for investigating the mechanism of exercise-induced bone formation. Mean difference in tibia weight between left and right in A/J mice was significantly higher than that in AKR/N strain. However we were unable to find any difference of tibia weight in the same strain. Therefore, these results imply that difference of hereditary and exercise-induced bone formation might be basically con-trolled by genomic factors.

DESCENTE SPORTS SCIENCE Vol.13/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE