Countercurrent centrifugal elutriation was used to separate, on the
basis of size, isolated growth-plate chondrocytes in chicks. The mean
cellular volume, activity of alkaline phosphatase, and synthesis of type-X
collagen increased progressively in each of seven successive fractions.
Slices of tissues that contained either proliferating or hypertrophic
chondrocytes were also removed by manual dissection from the superficial
and deep regions of the growth plate. These cells demonstrated differences
in size and biochemistry that were similar to those observed in
chondrocytes that were separated by elutriation. These differences included
increased synthesis of proteoglycan and collagen in the larger
chondrocytes. Radiolabeled hypertrophic chondrocytes were mixed with
unlabeled resting and proliferating chondrocytes, and then were separated
by elutriation. The radioactivity was recovered in fractions that contained
the largest cells, confirming that differences in the sizes of the cells
can be used to effect a zonal separation by centrifugal elutriation.