Chondrocyte differentiation and bone growth during the development of the cartilaginous skeleton of chickens]

Certain local alterations in functional and reproductive activity of chondrocytes were stated at the development of the cartilage skeleton. In epiphyses chondrocytes gradually pass into the phase of rest (G0) with subsequent multiplication during the process of skeletal development. In these structures biosynthesis of nonsulfated proteoglycans predominate, in time, while in other cartilage zones--that of sulfated ones. Proofs are furnished on gradual transition of epiphyseal chondrocytes into the state peculiar for cells of the proliferative zone accompanied by an intensified biosynthesis of sulfated proteoglycans and collagenous proteins. Owing to these peculiarities they can be compared with the cells of the reserve zone in the mammalian metaepiphyseal cartilage. It was stated that intensity of chondrogenesis and growth of bones are affected by several processes: intensity of chondrocyte multiplication, the rate of their repeated division in the proliferative zone, the velosity with which the cells transfer into the state of hypertrophy and the rate of the periostal bone formation at the border-line of metaphysis and diaphysis.